Add Markdown import from Obsidian (Stage 8)

- md-to-tiptap.ts: remark-based converter (headings, lists, blockquotes,
  code blocks, bold/italic/strike, links, images, hr)
- Obsidian ![[wikilink]] stripped, [[link|alias]] → plain text
- POST /api/admin/import-md: parses frontmatter (gray-matter) + converts content
- LessonEditor: "Импорт .md" button populates editor without auto-save
- ROADMAP: marked Stages 2, 3, 5, 6, 7, 8 as complete, fixed numbering

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/admin/lesson-editor.tsx

@@ -6,7 +6,7 @@ import StarterKit from "@tiptap/starter-kit";
 import Image from "@tiptap/extension-image";
 import Link from "@tiptap/extension-link";
 import Placeholder from "@tiptap/extension-placeholder";
-import { Save, Eye } from "lucide-react";
+import { Save, Eye, FileUp } from "lucide-react";
 import { saveLesson } from "@/app/admin/courses/[courseId]/modules/[moduleId]/lessons/[lessonId]/actions";
 
 interface LessonData {
@@ -32,6 +32,8 @@ export function LessonEditor({
   const [kinescopeId, setKinescopeId] = useState(lesson.kinescopeId);
   const [published, setPublished] = useState(lesson.published);
   const [uploading, setUploading] = useState(false);
+  const [importing, setImporting] = useState(false);
+  const [importError, setImportError] = useState<string | null>(null);
   const [saved, setSaved] = useState(false);
   const [pending, startTransition] = useTransition();
 
@@ -78,6 +80,34 @@ export function LessonEditor({
     input.click();
   }, [editor]);
 
+  const importMd = useCallback(() => {
+    const input = document.createElement("input");
+    input.type = "file";
+    input.accept = ".md";
+    input.onchange = async () => {
+      const file = input.files?.[0];
+      if (!file || !editor) return;
+      setImporting(true);
+      setImportError(null);
+      try {
+        const fd = new FormData();
+        fd.append("file", file);
+        const res = await fetch("/api/admin/import-md", { method: "POST", body: fd });
+        if (!res.ok) throw new Error("Ошибка импорта");
+        const data = await res.json();
+        if (data.title) setTitle(data.title);
+        if (data.kinescopeId) setKinescopeId(data.kinescopeId);
+        if (data.published !== null) setPublished(data.published);
+        if (data.content) editor.commands.setContent(data.content);
+      } catch {
+        setImportError("Не удалось импортировать файл");
+      } finally {
+        setImporting(false);
+      }
+    };
+    input.click();
+  }, [editor]);
+
   function handleSave() {
     if (!editor) return;
     startTransition(async () => {
@@ -125,6 +155,17 @@ export function LessonEditor({
         </button>
 
         <div className="flex items-center gap-2">
+          <button
+            type="button"
+            onClick={importMd}
+            disabled={importing || pending}
+            className="btn-aubade flex items-center gap-1.5 px-4 py-2 text-sm"
+            title="Импортировать из .md файла Obsidian"
+            style={{ opacity: importing || pending ? 0.6 : 1 }}
+          >
+            <FileUp size={14} />
+            {importing ? "Импорт..." : "Импорт .md"}
+          </button>
           <a
             href={`/courses/${courseSlug}/lessons/${lesson.id}`}
             target="_blank"
@@ -149,6 +190,12 @@ export function LessonEditor({
         </div>
       </div>
 
+      {importError && (
+        <p className="text-xs px-3 py-2" style={{ background: "oklch(0.577 0.245 27.325 / 0.1)", color: "oklch(0.577 0.245 27.325)", border: "1px solid oklch(0.577 0.245 27.325 / 0.3)" }}>
+          {importError}
+        </p>
+      )}
+
       {/* Title */}
       <div className="space-y-1">
         <label className="text-xs font-bold uppercase tracking-widest" style={{ color: "var(--muted-foreground)" }}>