Enrich lesson comments: Markdown formatting, edit, higher limit

Add a formatting toolbar + safe Markdown rendering (react-markdown +
rehype-sanitize), raise the length limit 2000 -> 10000, and let authors
edit their own comments (new editComment action + editedAt column shown
as an 'изменено' badge).

package-lock.json

@@ -41,6 +41,8 @@
         "playwright-core": "^1.61.1",
         "react": "19.2.4",
         "react-dom": "19.2.4",
+        "react-markdown": "^10.1.0",
+        "rehype-sanitize": "^6.0.0",
         "remark-parse": "^11.0.0",
         "resend": "^6.10.0",
         "sonner": "^2.0.7",
@@ -5092,9 +5094,26 @@
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-      "devOptional": true,
       "license": "MIT"
     },
+    "node_modules/@types/estree-jsx": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/@types/estree-jsx/-/estree-jsx-1.0.5.tgz",
+      "integrity": "sha512-52CcUVNFyfb1A2ALocQw/Dd1BQFNmSdkuC3BkZ6iqhdMfQz7JWOFRuJFloOzjk+6WijU56m9oKXFAXc7o3Towg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/estree": "*"
+      }
+    },
+    "node_modules/@types/hast": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/hast/-/hast-3.0.5.tgz",
+      "integrity": "sha512-rp/ezSWaD1m44dPKICGhiskI13nVr7qTloFwDa/IYkhhf5nzwP+zIQcIJh3WIFSBOy/H1PzB40jPjMDksN4F+g==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "*"
+      }
+    },
     "node_modules/@types/jsdom": {
       "version": "28.0.3",
       "resolved": "https://registry.npmjs.org/@types/jsdom/-/jsdom-28.0.3.tgz",
@@ -5518,6 +5537,12 @@
         "url": "https://opencollective.com/eslint"
       }
     },
+    "node_modules/@ungap/structured-clone": {
+      "version": "1.3.3",
+      "resolved": "https://registry.npmjs.org/@ungap/structured-clone/-/structured-clone-1.3.3.tgz",
+      "integrity": "sha512-60YRaenCQcVjYEKOcG824+DRGGIQ3VKErcBoAEDJZz5bKIs2ZG+X/H9Nk+Q6EVkwJk5QNApxbrc5QtBSwtrXAg==",
+      "license": "ISC"
+    },
     "node_modules/@unrs/resolver-binding-android-arm-eabi": {
       "version": "1.11.1",
       "resolved": "https://registry.npmjs.org/@unrs/resolver-binding-android-arm-eabi/-/resolver-binding-android-arm-eabi-1.11.1.tgz",
@@ -6662,6 +6687,16 @@
         "node": ">=12"
       }
     },
+    "node_modules/ccount": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/ccount/-/ccount-2.0.1.tgz",
+      "integrity": "sha512-eyrF0jiFpY+3drT6383f1qhkbGsLSifNAjA61IUjZjmLCWjItY6LB9ft9YhoDgwfmclB2zhu51Lc7+95b8NRAg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/chai": {
       "version": "6.2.2",
       "resolved": "https://registry.npmjs.org/chai/-/chai-6.2.2.tgz",
@@ -6699,6 +6734,36 @@
         "url": "https://github.com/sponsors/wooorm"
       }
     },
+    "node_modules/character-entities-html4": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/character-entities-html4/-/character-entities-html4-2.1.0.tgz",
+      "integrity": "sha512-1v7fgQRj6hnSwFpq1Eu0ynr/CDEw0rXo2B61qXrLNdHZmPKgb7fqS1a2JwF0rISo9q77jDI8VMEHoApn8qDoZA==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
+    "node_modules/character-entities-legacy": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/character-entities-legacy/-/character-entities-legacy-3.0.0.tgz",
+      "integrity": "sha512-RpPp0asT/6ufRm//AJVwpViZbGM/MkjQFxJccQRHmISF/22NBtsHqAWmL+/pmkPWoIUJdWyeVleTl1wydHATVQ==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
+    "node_modules/character-reference-invalid": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/character-reference-invalid/-/character-reference-invalid-2.0.1.tgz",
+      "integrity": "sha512-iBZ4F4wRbyORVsu0jPV7gXkOsGYjGHPmAyv+HiHG8gi5PtC9KI2j1+v8/tlibRvjoWX027ypmG/n0HtO5t7unw==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/chart.js": {
       "version": "4.5.1",
       "resolved": "https://registry.npmjs.org/chart.js/-/chart.js-4.5.1.tgz",
@@ -6785,6 +6850,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/comma-separated-tokens": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/comma-separated-tokens/-/comma-separated-tokens-2.0.3.tgz",
+      "integrity": "sha512-Fu4hJdvzeylCfQPp9SGWidpzrMs7tTrlu6Vb8XGaRGck8QSNZJJp538Wrb60Lax4fPwR64ViY468OIUTbRlGZg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/commander": {
       "version": "12.1.0",
       "resolved": "https://registry.npmjs.org/commander/-/commander-12.1.0.tgz",
@@ -8167,6 +8242,16 @@
         "node": ">=4.0"
       }
     },
+    "node_modules/estree-util-is-identifier-name": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/estree-util-is-identifier-name/-/estree-util-is-identifier-name-3.0.0.tgz",
+      "integrity": "sha512-hFtqIDZTIUZ9BXLb8y4pYGyk6+wekIivNVTcmvk8NoOh+VeRn5y6cEHzbURrWbfp1fIqdVipilzj+lfaadNZmg==",
+      "license": "MIT",
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/estree-walker": {
       "version": "3.0.3",
       "resolved": "https://registry.npmjs.org/estree-walker/-/estree-walker-3.0.3.tgz",
@@ -8898,6 +8983,61 @@
         "node": ">= 0.4"
       }
     },
+    "node_modules/hast-util-sanitize": {
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/hast-util-sanitize/-/hast-util-sanitize-5.0.2.tgz",
+      "integrity": "sha512-3yTWghByc50aGS7JlGhk61SPenfE/p1oaFeNwkOOyrscaOkMGrcW9+Cy/QAIOBpZxP1yqDIzFMR0+Np0i0+usg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/hast": "^3.0.0",
+        "@ungap/structured-clone": "^1.0.0",
+        "unist-util-position": "^5.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
+    "node_modules/hast-util-to-jsx-runtime": {
+      "version": "2.3.6",
+      "resolved": "https://registry.npmjs.org/hast-util-to-jsx-runtime/-/hast-util-to-jsx-runtime-2.3.6.tgz",
+      "integrity": "sha512-zl6s8LwNyo1P9uw+XJGvZtdFF1GdAkOg8ujOw+4Pyb76874fLps4ueHXDhXWdk6YHQ6OgUtinliG7RsYvCbbBg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/estree": "^1.0.0",
+        "@types/hast": "^3.0.0",
+        "@types/unist": "^3.0.0",
+        "comma-separated-tokens": "^2.0.0",
+        "devlop": "^1.0.0",
+        "estree-util-is-identifier-name": "^3.0.0",
+        "hast-util-whitespace": "^3.0.0",
+        "mdast-util-mdx-expression": "^2.0.0",
+        "mdast-util-mdx-jsx": "^3.0.0",
+        "mdast-util-mdxjs-esm": "^2.0.0",
+        "property-information": "^7.0.0",
+        "space-separated-tokens": "^2.0.0",
+        "style-to-js": "^1.0.0",
+        "unist-util-position": "^5.0.0",
+        "vfile-message": "^4.0.0"
+      },
+      "funding": {
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+        "url": "https://opencollective.com/unified"
+      }
+    },
+    "node_modules/hast-util-whitespace": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/hast-util-whitespace/-/hast-util-whitespace-3.0.0.tgz",
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+      "dependencies": {
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+      },
+      "funding": {
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     "node_modules/hermes-estree": {
       "version": "0.25.1",
       "resolved": "https://registry.npmjs.org/hermes-estree/-/hermes-estree-0.25.1.tgz",
@@ -8944,6 +9084,16 @@
       "license": "MIT",
       "optional": true
     },
+    "node_modules/html-url-attributes": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/html-url-attributes/-/html-url-attributes-3.0.1.tgz",
+      "integrity": "sha512-ol6UPyBWqsrO6EJySPz2O7ZSr856WDrEzM5zMqp+FJJLGMW35cLYmmZnl0vztAZxRUoNZJFTCohfjuIJ8I4QBQ==",
+      "license": "MIT",
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/htmlparser2": {
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       "resolved": "https://registry.npmjs.org/htmlparser2/-/htmlparser2-10.1.0.tgz",
@@ -9046,6 +9196,12 @@
         "node": ">=12"
       }
     },
+    "node_modules/inline-style-parser": {
+      "version": "0.2.7",
+      "resolved": "https://registry.npmjs.org/inline-style-parser/-/inline-style-parser-0.2.7.tgz",
+      "integrity": "sha512-Nb2ctOyNR8DqQoR0OwRG95uNWIC0C1lCgf5Naz5H6Ji72KZ8OcFZLz2P5sNgwlyoJ8Yif11oMuYs5pBQa86csA==",
+      "license": "MIT"
+    },
     "node_modules/internal-slot": {
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       "resolved": "https://registry.npmjs.org/internal-slot/-/internal-slot-1.1.0.tgz",
@@ -9070,6 +9226,30 @@
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       }
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+    "node_modules/is-alphabetical": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/is-alphabetical/-/is-alphabetical-2.0.1.tgz",
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+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
+    "node_modules/is-alphanumerical": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/is-alphanumerical/-/is-alphanumerical-2.0.1.tgz",
+      "integrity": "sha512-hmbYhX/9MUMF5uh7tOXyK/n0ZvWpad5caBA17GsC6vyuCqaWliRG5K1qS9inmUhEMaOBIW7/whAnSwveW/LtZw==",
+      "license": "MIT",
+      "dependencies": {
+        "is-alphabetical": "^2.0.0",
+        "is-decimal": "^2.0.0"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/is-array-buffer": {
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@@ -9228,6 +9408,16 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/is-decimal": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/is-decimal/-/is-decimal-2.0.1.tgz",
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+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
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@@ -9296,6 +9486,16 @@
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       }
     },
+    "node_modules/is-hexadecimal": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/is-hexadecimal/-/is-hexadecimal-2.0.1.tgz",
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+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/is-map": {
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@@ -10114,6 +10314,16 @@
       "devOptional": true,
       "license": "Apache-2.0"
     },
+    "node_modules/longest-streak": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/longest-streak/-/longest-streak-3.1.0.tgz",
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+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/loose-envify": {
       "version": "1.4.0",
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@@ -10240,6 +10450,122 @@
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+    "node_modules/mdast-util-mdx-expression": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/mdast-util-mdx-expression/-/mdast-util-mdx-expression-2.0.1.tgz",
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+      "dependencies": {
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+        "@types/hast": "^3.0.0",
+        "@types/mdast": "^4.0.0",
+        "devlop": "^1.0.0",
+        "mdast-util-from-markdown": "^2.0.0",
+        "mdast-util-to-markdown": "^2.0.0"
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       "resolved": "https://registry.npmjs.org/mdast-util-to-string/-/mdast-util-to-string-4.0.0.tgz",
@@ -11243,6 +11569,31 @@
         "node": ">=6"
       }
     },
+    "node_modules/parse-entities": {
+      "version": "4.0.2",
+      "resolved": "https://registry.npmjs.org/parse-entities/-/parse-entities-4.0.2.tgz",
+      "integrity": "sha512-GG2AQYWoLgL877gQIKeRPGO1xF9+eG1ujIb5soS5gPvLQ1y2o8FL90w2QWNdf9I361Mpp7726c+lj3U0qK1uGw==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "^2.0.0",
+        "character-entities-legacy": "^3.0.0",
+        "character-reference-invalid": "^2.0.0",
+        "decode-named-character-reference": "^1.0.0",
+        "is-alphanumerical": "^2.0.0",
+        "is-decimal": "^2.0.0",
+        "is-hexadecimal": "^2.0.0"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
+    "node_modules/parse-entities/node_modules/@types/unist": {
+      "version": "2.0.11",
+      "resolved": "https://registry.npmjs.org/@types/unist/-/unist-2.0.11.tgz",
+      "integrity": "sha512-CmBKiL6NNo/OqgmMn95Fk9Whlp2mtvIv+KNpQKN2F4SjvrEesubTRWGYSg+BnWZOnlCaSTU1sMpsBOzgbYhnsA==",
+      "license": "MIT"
+    },
     "node_modules/parse5": {
       "version": "8.0.1",
       "resolved": "https://registry.npmjs.org/parse5/-/parse5-8.0.1.tgz",
@@ -11647,6 +11998,16 @@
       "devOptional": true,
       "license": "ISC"
     },
+    "node_modules/property-information": {
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/property-information/-/property-information-7.2.0.tgz",
+      "integrity": "sha512-IAtzIB6sUiWaJYrX9smp3V46pBGbBeLFRGdh25kg1334VcBlD8HzhPeNIWQH9zhGmo2itIe25EHt9dQP7G5hmg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/prosemirror-changeset": {
       "version": "2.4.0",
       "resolved": "https://registry.npmjs.org/prosemirror-changeset/-/prosemirror-changeset-2.4.0.tgz",
@@ -11937,6 +12298,33 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/react-markdown": {
+      "version": "10.1.0",
+      "resolved": "https://registry.npmjs.org/react-markdown/-/react-markdown-10.1.0.tgz",
+      "integrity": "sha512-qKxVopLT/TyA6BX3Ue5NwabOsAzm0Q7kAPwq6L+wWDwisYs7R8vZ0nRXqq6rkueboxpkjvLGU9fWifiX/ZZFxQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/hast": "^3.0.0",
+        "@types/mdast": "^4.0.0",
+        "devlop": "^1.0.0",
+        "hast-util-to-jsx-runtime": "^2.0.0",
+        "html-url-attributes": "^3.0.0",
+        "mdast-util-to-hast": "^13.0.0",
+        "remark-parse": "^11.0.0",
+        "remark-rehype": "^11.0.0",
+        "unified": "^11.0.0",
+        "unist-util-visit": "^5.0.0",
+        "vfile": "^6.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      },
+      "peerDependencies": {
+        "@types/react": ">=18",
+        "react": ">=18"
+      }
+    },
     "node_modules/readdirp": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-4.1.2.tgz",
@@ -11995,6 +12383,20 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/rehype-sanitize": {
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/rehype-sanitize/-/rehype-sanitize-6.0.0.tgz",
+      "integrity": "sha512-CsnhKNsyI8Tub6L4sm5ZFsme4puGfc6pYylvXo1AeqaGbjOYyzNv3qZPwvs0oMJ39eryyeOdmxwUIo94IpEhqg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/hast": "^3.0.0",
+        "hast-util-sanitize": "^5.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/remark-parse": {
       "version": "11.0.0",
       "resolved": "https://registry.npmjs.org/remark-parse/-/remark-parse-11.0.0.tgz",
@@ -12011,6 +12413,23 @@
         "url": "https://opencollective.com/unified"
       }
     },
+    "node_modules/remark-rehype": {
+      "version": "11.1.2",
+      "resolved": "https://registry.npmjs.org/remark-rehype/-/remark-rehype-11.1.2.tgz",
+      "integrity": "sha512-Dh7l57ianaEoIpzbp0PC9UKAdCSVklD8E5Rpw7ETfbTl3FqcOOgq5q2LVDhgGCkaBv7p24JXikPdvhhmHvKMsw==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/hast": "^3.0.0",
+        "@types/mdast": "^4.0.0",
+        "mdast-util-to-hast": "^13.0.0",
+        "unified": "^11.0.0",
+        "vfile": "^6.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/remeda": {
       "version": "2.33.4",
       "resolved": "https://registry.npmjs.org/remeda/-/remeda-2.33.4.tgz",
@@ -12551,6 +12970,16 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/space-separated-tokens": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/space-separated-tokens/-/space-separated-tokens-2.0.2.tgz",
+      "integrity": "sha512-PEGlAwrG8yXGXRjW32fGbg66JAlOAwbObuqVoJpv/mRgoWDQfgH1wDPvtzWyUSNAXBGSk8h755YDbbcEy3SH2Q==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/split2": {
       "version": "4.2.0",
       "resolved": "https://registry.npmjs.org/split2/-/split2-4.2.0.tgz",
@@ -12734,6 +13163,20 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+    "node_modules/stringify-entities": {
+      "version": "4.0.4",
+      "resolved": "https://registry.npmjs.org/stringify-entities/-/stringify-entities-4.0.4.tgz",
+      "integrity": "sha512-IwfBptatlO+QCJUo19AqvrPNqlVMpW9YEL2LIVY+Rpv2qsjCGxaDLNRgeGsQWJhfItebuJhsGSLjaBbNSQ+ieg==",
+      "license": "MIT",
+      "dependencies": {
+        "character-entities-html4": "^2.0.0",
+        "character-entities-legacy": "^3.0.0"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/strip-bom": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/strip-bom/-/strip-bom-3.0.0.tgz",
@@ -12778,6 +13221,24 @@
       ],
       "license": "MIT"
     },
+    "node_modules/style-to-js": {
+      "version": "1.1.21",
+      "resolved": "https://registry.npmjs.org/style-to-js/-/style-to-js-1.1.21.tgz",
+      "integrity": "sha512-RjQetxJrrUJLQPHbLku6U/ocGtzyjbJMP9lCNK7Ag0CNh690nSH8woqWH9u16nMjYBAok+i7JO1NP2pOy8IsPQ==",
+      "license": "MIT",
+      "dependencies": {
+        "style-to-object": "1.0.14"
+      }
+    },
+    "node_modules/style-to-object": {
+      "version": "1.0.14",
+      "resolved": "https://registry.npmjs.org/style-to-object/-/style-to-object-1.0.14.tgz",
+      "integrity": "sha512-LIN7rULI0jBscWQYaSswptyderlarFkjQ+t79nzty8tcIAceVomEVlLzH5VP4Cmsv6MtKhs7qaAiwlcp+Mgaxw==",
+      "license": "MIT",
+      "dependencies": {
+        "inline-style-parser": "0.2.7"
+      }
+    },
     "node_modules/styled-jsx": {
       "version": "5.1.6",
       "resolved": "https://registry.npmjs.org/styled-jsx/-/styled-jsx-5.1.6.tgz",
@@ -13026,6 +13487,16 @@
         "node": ">=20"
       }
     },
+    "node_modules/trim-lines": {
+      "version": "3.0.1",
+      "resolved": "https://registry.npmjs.org/trim-lines/-/trim-lines-3.0.1.tgz",
+      "integrity": "sha512-kRj8B+YHZCc9kQYdWfJB2/oUl9rA99qbowYYBtr4ui4mZyAQ2JpvVBd/6U2YloATfqBhBTSMhTpgBHtU0Mf3Rg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
+    },
     "node_modules/trough": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/trough/-/trough-2.2.0.tgz",
@@ -13334,6 +13805,32 @@
         "url": "https://opencollective.com/unified"
       }
     },
+    "node_modules/unist-util-is": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/unist-util-is/-/unist-util-is-6.0.1.tgz",
+      "integrity": "sha512-LsiILbtBETkDz8I9p1dQ0uyRUWuaQzd/cuEeS1hoRSyW5E5XGmTzlwY1OrNzzakGowI9Dr/I8HVaw4hTtnxy8g==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "^3.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
+    "node_modules/unist-util-position": {
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/unist-util-position/-/unist-util-position-5.0.0.tgz",
+      "integrity": "sha512-fucsC7HjXvkB5R3kTCO7kUjRdrS0BJt3M/FPxmHMBOm8JQi2BsHAHFsy27E0EolP8rp0NzXsJ+jNPyDWvOJZPA==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "^3.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/unist-util-stringify-position": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/unist-util-stringify-position/-/unist-util-stringify-position-4.0.0.tgz",
@@ -13347,6 +13844,35 @@
         "url": "https://opencollective.com/unified"
       }
     },
+    "node_modules/unist-util-visit": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/unist-util-visit/-/unist-util-visit-5.1.0.tgz",
+      "integrity": "sha512-m+vIdyeCOpdr/QeQCu2EzxX/ohgS8KbnPDgFni4dQsfSCtpz8UqDyY5GjRru8PDKuYn7Fq19j1CQ+nJSsGKOzg==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "^3.0.0",
+        "unist-util-is": "^6.0.0",
+        "unist-util-visit-parents": "^6.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
+    "node_modules/unist-util-visit-parents": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/unist-util-visit-parents/-/unist-util-visit-parents-6.0.2.tgz",
+      "integrity": "sha512-goh1s1TBrqSqukSc8wrjwWhL0hiJxgA8m4kFxGlQ+8FYQ3C/m11FcTs4YYem7V664AhHVvgoQLk890Ssdsr2IQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@types/unist": "^3.0.0",
+        "unist-util-is": "^6.0.0"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/unified"
+      }
+    },
     "node_modules/unrs-resolver": {
       "version": "1.11.1",
       "resolved": "https://registry.npmjs.org/unrs-resolver/-/unrs-resolver-1.11.1.tgz",
@@ -13964,6 +14490,16 @@
       "peerDependencies": {
         "zod": "^3.25.0 || ^4.0.0"
       }
+    },
+    "node_modules/zwitch": {
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/zwitch/-/zwitch-2.0.4.tgz",
+      "integrity": "sha512-bXE4cR/kVZhKZX/RjPEflHaKVhUVl85noU3v6b8apfQEc1x4A+zBxjZ4lN8LqGd6WZ3dl98pY4o717VFmoPp+A==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/wooorm"
+      }
     }
   }
 }

package.json

@@ -47,6 +47,8 @@
     "playwright-core": "^1.61.1",
     "react": "19.2.4",
     "react-dom": "19.2.4",
+    "react-markdown": "^10.1.0",
+    "rehype-sanitize": "^6.0.0",
     "remark-parse": "^11.0.0",
     "resend": "^6.10.0",
     "sonner": "^2.0.7",

prisma/migrations/20260731120000_add_comment_edited_at/migration.sql

@@ -0,0 +1,2 @@
+-- Комментарии под уроками: метка «изменено» (ставится только при редактировании текста)
+ALTER TABLE "LessonComment" ADD COLUMN "editedAt" TIMESTAMP(3);

prisma/schema.prisma

@@ -359,6 +359,7 @@ model LessonComment {
   text      String
   deleted   Boolean   @default(false)
   createdAt DateTime  @default(now())
+  editedAt  DateTime?
   parentId  String?
 
   lesson  Lesson          @relation(fields: [lessonId], references: [id], onDelete: Cascade)

src/app/globals.css

@@ -241,3 +241,35 @@
   border-left-color: #E8F0D8;
   background-color: var(--sidebar-surface);
 }
+
+/* Markdown-разметка в комментариях под уроками (react-markdown) */
+.comment-md > :first-child { margin-top: 0; }
+.comment-md > :last-child { margin-bottom: 0; }
+.comment-md p { margin: 0 0 0.5rem; }
+.comment-md strong { font-weight: 700; }
+.comment-md em { font-style: italic; }
+.comment-md a { color: var(--foreground); text-decoration: underline; text-underline-offset: 2px; }
+.comment-md ul { list-style: disc; padding-left: 1.4rem; margin: 0 0 0.5rem; }
+.comment-md ol { list-style: decimal; padding-left: 1.4rem; margin: 0 0 0.5rem; }
+.comment-md li { margin: 0.15rem 0; }
+.comment-md blockquote {
+  border-left: 2px solid var(--border);
+  padding-left: 0.75rem;
+  margin: 0 0 0.5rem;
+  color: var(--muted-foreground);
+}
+.comment-md code {
+  font-family: var(--font-mono, monospace);
+  font-size: 0.9em;
+  background: var(--color-surface);
+  padding: 0.05rem 0.3rem;
+  border-radius: 2px;
+}
+.comment-md pre {
+  background: var(--color-surface);
+  padding: 0.6rem 0.75rem;
+  border-radius: 2px;
+  overflow-x: auto;
+  margin: 0 0 0.5rem;
+}
+.comment-md pre code { background: none; padding: 0; }

src/components/student/lesson-comments.tsx

@@ -1,13 +1,18 @@
 "use client";
 
-import { useState, useTransition } from "react";
+import { useRef, useState, useTransition, type ReactNode } from "react";
-import { addComment, deleteComment } from "@/lib/actions/student-actions";
+import ReactMarkdown from "react-markdown";
+import rehypeSanitize from "rehype-sanitize";
+import { addComment, deleteComment, editComment } from "@/lib/actions/student-actions";
+
+const MAX_LEN = 10000;
 
 type Reply = {
   id: string;
   text: string;
   deleted: boolean;
   createdAt: Date;
+  editedAt: Date | null;
   user: { id: string; name: string };
 };
 
@@ -16,6 +21,7 @@ type Comment = {
   text: string;
   deleted: boolean;
   createdAt: Date;
+  editedAt: Date | null;
   user: { id: string; name: string };
   replies: Reply[];
 };
@@ -38,10 +44,146 @@ function formatDate(date: Date) {
   });
 }
 
+// Renders comment text as sanitized Markdown (no raw HTML, safe links).
+function CommentBody({ text }: { text: string }) {
+  return (
+    <div className="comment-md text-sm leading-relaxed break-words">
+      <ReactMarkdown
+        rehypePlugins={[rehypeSanitize]}
+        components={{
+          a: ({ ...props }) => <a {...props} target="_blank" rel="noopener noreferrer" />,
+        }}
+      >
+        {text}
+      </ReactMarkdown>
+    </div>
+  );
+}
+
+const toolbarBtnStyle = {
+  border: "2px solid var(--border)",
+  color: "var(--foreground)",
+  background: "var(--background)",
+  minWidth: "30px",
+} as const;
+
+function ToolbarButton({
+  title,
+  onClick,
+  disabled,
+  children,
+}: {
+  title: string;
+  onClick: () => void;
+  disabled?: boolean;
+  children: ReactNode;
+}) {
+  return (
+    <button
+      type="button"
+      title={title}
+      disabled={disabled}
+      onClick={onClick}
+      className="text-xs px-2 py-1 leading-none transition-colors"
+      style={toolbarBtnStyle}
+      onMouseEnter={(e) => (e.currentTarget.style.background = "var(--accent)")}
+      onMouseLeave={(e) => (e.currentTarget.style.background = "var(--background)")}
+    >
+      {children}
+    </button>
+  );
+}
+
+interface EditorProps {
+  value: string;
+  onChange: (v: string) => void;
+  placeholder: string;
+  disabled?: boolean;
+  rows?: number;
+}
+
+// Textarea + Markdown formatting toolbar + character counter. Reused for the
+// new comment, replies, and inline editing.
+function CommentEditor({ value, onChange, placeholder, disabled, rows = 3 }: EditorProps) {
+  const ref = useRef<HTMLTextAreaElement>(null);
+
+  // Wrap the current selection with before/after markers.
+  function wrap(before: string, after: string, placeholderText: string) {
+    const el = ref.current;
+    if (!el) return;
+    const start = el.selectionStart;
+    const end = el.selectionEnd;
+    const selected = value.slice(start, end) || placeholderText;
+    const next = value.slice(0, start) + before + selected + after + value.slice(end);
+    onChange(next);
+    requestAnimationFrame(() => {
+      el.focus();
+      el.setSelectionRange(start + before.length, start + before.length + selected.length);
+    });
+  }
+
+  // Prefix each selected line (for lists and quotes).
+  function prefixLines(prefix: string) {
+    const el = ref.current;
+    if (!el) return;
+    const start = el.selectionStart;
+    const end = el.selectionEnd;
+    const lineStart = value.lastIndexOf("\n", start - 1) + 1;
+    const block = value.slice(lineStart, end);
+    const prefixed = block
+      .split("\n")
+      .map((l) => prefix + l)
+      .join("\n");
+    const next = value.slice(0, lineStart) + prefixed + value.slice(end);
+    onChange(next);
+    requestAnimationFrame(() => {
+      el.focus();
+      el.setSelectionRange(lineStart, lineStart + prefixed.length);
+    });
+  }
+
+  return (
+    <div>
+      <div className="flex flex-wrap gap-1 mb-2">
+        <ToolbarButton title="Жирный" disabled={disabled} onClick={() => wrap("**", "**", "текст")}><b>Ж</b></ToolbarButton>
+        <ToolbarButton title="Курсив" disabled={disabled} onClick={() => wrap("*", "*", "текст")}><i>К</i></ToolbarButton>
+        <ToolbarButton title="Список" disabled={disabled} onClick={() => prefixLines("- ")}>•</ToolbarButton>
+        <ToolbarButton title="Цитата" disabled={disabled} onClick={() => prefixLines("> ")}>»</ToolbarButton>
+        <ToolbarButton title="Код" disabled={disabled} onClick={() => wrap("`", "`", "код")}>{"</>"}</ToolbarButton>
+        <ToolbarButton title="Ссылка" disabled={disabled} onClick={() => wrap("[", "](https://)", "текст")}>🔗</ToolbarButton>
+      </div>
+      <textarea
+        ref={ref}
+        value={value}
+        onChange={(e) => onChange(e.target.value)}
+        placeholder={placeholder}
+        rows={rows}
+        maxLength={MAX_LEN}
+        disabled={disabled}
+        className="w-full text-sm p-3 resize-y"
+        style={{
+          border: "2px solid var(--border)",
+          backgroundColor: "var(--background)",
+          color: "var(--foreground)",
+          outline: "none",
+          fontFamily: "inherit",
+        }}
+        onFocus={(e) => (e.target.style.borderColor = "var(--foreground)")}
+        onBlur={(e) => (e.target.style.borderColor = "var(--border)")}
+      />
+      <div className="text-xs mt-1" style={{ color: "var(--muted-foreground)" }}>
+        Поддерживается форматирование Markdown{value.length > 0 ? ` · ${value.length}/${MAX_LEN}` : ""}
+      </div>
+    </div>
+  );
+}
+
 export function LessonComments({ lessonId, slug, comments, currentUserId, currentUserRole }: Props) {
   const [text, setText] = useState("");
   const [replyToId, setReplyToId] = useState<string | null>(null);
   const [replyText, setReplyText] = useState("");
+  const [editingId, setEditingId] = useState<string | null>(null);
+  const [editText, setEditText] = useState("");
   const [isPending, startTransition] = useTransition();
   const [error, setError] = useState<string | null>(null);
 
@@ -74,6 +216,19 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
     });
   }
 
+  function handleEdit(commentId: string) {
+    if (!editText.trim()) return;
+    startTransition(async () => {
+      try {
+        await editComment(commentId, lessonId, slug, editText.trim());
+        setEditingId(null);
+        setEditText("");
+      } catch {
+        // ignore
+      }
+    });
+  }
+
   function handleDelete(commentId: string) {
     startTransition(async () => {
       try {
@@ -84,6 +239,89 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
     });
   }
 
+  function renderNode(node: Comment | Reply, isReply: boolean) {
+    const isOwn = node.user.id === currentUserId;
+    const editing = editingId === node.id;
+    return (
+      <div className="flex-1 min-w-0">
+        <div className="flex items-center gap-2 mb-1 flex-wrap">
+          <span className="text-sm font-bold">{node.user.name}</span>
+          <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
+            {formatDate(node.createdAt)}
+            {node.editedAt && !node.deleted ? " · изменено" : ""}
+          </span>
+        </div>
+
+        {node.deleted ? (
+          <p className="text-sm italic" style={{ color: "var(--muted-foreground)" }}>
+            [Комментарий удалён]
+          </p>
+        ) : editing ? (
+          <div>
+            <CommentEditor value={editText} onChange={setEditText} placeholder="Измените комментарий..." disabled={isPending} rows={3} />
+            <div className="flex items-center gap-2 mt-2">
+              <button
+                onClick={() => handleEdit(node.id)}
+                disabled={isPending || !editText.trim()}
+                className="btn-aubade btn-aubade-accent text-sm"
+              >
+                {isPending ? "Сохранение..." : "Сохранить"}
+              </button>
+              <button
+                onClick={() => { setEditingId(null); setEditText(""); }}
+                disabled={isPending}
+                className="text-xs underline"
+                style={{ color: "var(--muted-foreground)" }}
+              >
+                Отмена
+              </button>
+            </div>
+          </div>
+        ) : (
+          <CommentBody text={node.text} />
+        )}
+
+        {!node.deleted && !editing && (
+          <div className="flex gap-3 mt-1">
+            {isOwn && (
+              <button
+                onClick={() => { setEditingId(node.id); setEditText(node.text); setReplyToId(null); }}
+                disabled={isPending}
+                className="text-xs underline"
+                style={{ color: "var(--muted-foreground)" }}
+              >
+                Изменить
+              </button>
+            )}
+            {(isOwn || canModerate) && (
+              <button
+                onClick={() => handleDelete(node.id)}
+                disabled={isPending}
+                className="text-xs underline"
+                style={{ color: "var(--muted-foreground)" }}
+              >
+                Удалить
+              </button>
+            )}
+            {!isReply && canModerate && (
+              <button
+                onClick={() => {
+                  setReplyToId(replyToId === node.id ? null : node.id);
+                  setReplyText("");
+                }}
+                disabled={isPending}
+                className="text-xs underline"
+                style={{ color: "var(--muted-foreground)" }}
+              >
+                {replyToId === node.id ? "Отмена" : "Ответить"}
+              </button>
+            )}
+          </div>
+        )}
+      </div>
+    );
+  }
+
   return (
     <div>
       <div className="space-y-5 mb-6">
@@ -107,72 +345,13 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
               >
                 {comment.user.name[0]?.toUpperCase() ?? "?"}
               </div>
-
+              {renderNode(comment, false)}
-              <div className="flex-1 min-w-0">
-                <div className="flex items-center gap-2 mb-1 flex-wrap">
-                  <span className="text-sm font-bold">{comment.user.name}</span>
-                  <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
-                    {formatDate(comment.createdAt)}
-                  </span>
             </div>
 
-                {comment.deleted ? (
+            {/* Inline reply form (under root) */}
-                  <p className="text-sm italic" style={{ color: "var(--muted-foreground)" }}>
-                    [Комментарий удалён]
-                  </p>
-                ) : (
-                  <p className="text-sm whitespace-pre-wrap break-words leading-relaxed">
-                    {comment.text}
-                  </p>
-                )}
-
-                <div className="flex gap-3 mt-1">
-                  {!comment.deleted && (comment.user.id === currentUserId || canModerate) && (
-                    <button
-                      onClick={() => handleDelete(comment.id)}
-                      disabled={isPending}
-                      className="text-xs underline"
-                      style={{ color: "var(--muted-foreground)" }}
-                    >
-                      Удалить
-                    </button>
-                  )}
-                  {!comment.deleted && canModerate && (
-                    <button
-                      onClick={() => {
-                        setReplyToId(replyToId === comment.id ? null : comment.id);
-                        setReplyText("");
-                      }}
-                      disabled={isPending}
-                      className="text-xs underline"
-                      style={{ color: "var(--muted-foreground)" }}
-                    >
-                      {replyToId === comment.id ? "Отмена" : "Ответить"}
-                    </button>
-                  )}
-                </div>
-
-                {/* Inline reply form */}
             {replyToId === comment.id && (
-                  <div className="mt-3">
+              <div className="mt-3 ml-11">
-                    <textarea
+                <CommentEditor value={replyText} onChange={setReplyText} placeholder="Напишите ответ..." disabled={isPending} rows={2} />
-                      value={replyText}
-                      onChange={(e) => setReplyText(e.target.value)}
-                      placeholder="Напишите ответ..."
-                      rows={2}
-                      maxLength={2000}
-                      disabled={isPending}
-                      className="w-full text-sm p-3 resize-y"
-                      style={{
-                        border: "2px solid var(--border)",
-                        backgroundColor: "var(--background)",
-                        color: "var(--foreground)",
-                        outline: "none",
-                        fontFamily: "inherit",
-                      }}
-                      onFocus={(e) => (e.target.style.borderColor = "var(--foreground)")}
-                      onBlur={(e) => (e.target.style.borderColor = "var(--border)")}
-                    />
                 <div className="flex justify-end mt-2">
                   <button
                     onClick={() => handleReply(comment.id)}
@@ -184,8 +363,6 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
                 </div>
               </div>
             )}
-              </div>
-            </div>
 
             {/* Replies */}
             {comment.replies.length > 0 && (
@@ -205,33 +382,7 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
                     >
                       {reply.user.name[0]?.toUpperCase() ?? "?"}
                     </div>
-                    <div className="flex-1 min-w-0">
+                    {renderNode(reply, true)}
-                      <div className="flex items-center gap-2 mb-1 flex-wrap">
-                        <span className="text-sm font-bold">{reply.user.name}</span>
-                        <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
-                          {formatDate(reply.createdAt)}
-                        </span>
-                      </div>
-                      {reply.deleted ? (
-                        <p className="text-sm italic" style={{ color: "var(--muted-foreground)" }}>
-                          [Комментарий удалён]
-                        </p>
-                      ) : (
-                        <p className="text-sm whitespace-pre-wrap break-words leading-relaxed">
-                          {reply.text}
-                        </p>
-                      )}
-                      {!reply.deleted && (reply.user.id === currentUserId || canModerate) && (
-                        <button
-                          onClick={() => handleDelete(reply.id)}
-                          disabled={isPending}
-                          className="text-xs mt-1 underline"
-                          style={{ color: "var(--muted-foreground)" }}
-                        >
-                          Удалить
-                        </button>
-                      )}
-                    </div>
                   </div>
                 ))}
               </div>
@@ -242,33 +393,13 @@ export function LessonComments({ lessonId, slug, comments, currentUserId, curren
 
       {/* New comment form */}
       <form onSubmit={handleAdd}>
-        <textarea
+        <CommentEditor value={text} onChange={setText} placeholder="Напишите комментарий..." disabled={isPending} rows={3} />
-          value={text}
-          onChange={(e) => setText(e.target.value)}
-          placeholder="Напишите комментарий..."
-          rows={3}
-          maxLength={2000}
-          disabled={isPending}
-          className="w-full text-sm p-3 resize-y"
-          style={{
-            border: "2px solid var(--border)",
-            backgroundColor: "var(--background)",
-            color: "var(--foreground)",
-            outline: "none",
-            fontFamily: "inherit",
-          }}
-          onFocus={(e) => (e.target.style.borderColor = "var(--foreground)")}
-          onBlur={(e) => (e.target.style.borderColor = "var(--border)")}
-        />
         {error && (
           <p className="text-xs mt-1" style={{ color: "oklch(0.577 0.245 27.325)" }}>
             {error}
           </p>
         )}
-        <div className="flex items-center justify-between mt-2">
+        <div className="flex items-center justify-end mt-2">
-          <span className="text-xs" style={{ color: "var(--muted-foreground)" }}>
-            {text.length > 0 ? `${text.length}/2000` : ""}
-          </span>
           <button
             type="submit"
             disabled={isPending || !text.trim()}

src/lib/actions/student-actions.ts

@@ -152,7 +152,7 @@ export async function addComment(lessonId: string, slug: string, text: string, p
   if (!session) throw new Error("Unauthorized");
 
   const trimmed = text.trim();
-  if (!trimmed || trimmed.length > 2000) throw new Error("Invalid text");
+  if (!trimmed || trimmed.length > 10000) throw new Error("Invalid text");
 
   const lesson = await prisma.lesson.findUnique({
     where: { id: lessonId },
@@ -228,3 +228,24 @@ export async function deleteComment(commentId: string, lessonId: string, slug: s
 
   revalidatePath(`/courses/${slug}/lessons/${lessonId}`);
 }
+
+export async function editComment(commentId: string, lessonId: string, slug: string, text: string) {
+  const session = await auth.api.getSession({ headers: await headers() });
+  if (!session) throw new Error("Unauthorized");
+
+  const trimmed = text.trim();
+  if (!trimmed || trimmed.length > 10000) throw new Error("Invalid text");
+
+  const comment = await prisma.lessonComment.findUnique({ where: { id: commentId } });
+  if (!comment) throw new Error("Not found");
+  if (comment.deleted) throw new Error("Comment deleted");
+  // Только автор может редактировать текст своего комментария (модераторы — только удаление).
+  if (comment.userId !== session.user.id) throw new Error("Forbidden");
+
+  await prisma.lessonComment.update({
+    where: { id: commentId },
+    data: { text: trimmed, editedAt: new Date() },
+  });
+
+  revalidatePath(`/courses/${slug}/lessons/${lessonId}`);
+}