Implement platform settings (Stage 9)

- Wire settings to actual platform behavior: maintenance mode, registration toggle,
  notification emails, curator feedback emails, email verification flag
- Add logo (logoUrl, showLogo) and social network links (YouTube, VK, Telegram) settings
- Show logo + school name dynamically in student layout header
- Add footer to student layout with org requisites and social links
- Register page: read settings server-side, validate terms checkbox with legal links
- Login page: show notice when redirected from closed registration
- Settings form: add Logo and Social Networks sections

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

src/app/(student)/layout.tsx

@@ -16,6 +16,17 @@ export default async function StudentLayout({ children }: { children: React.Reac
     if (maintenance === "true") redirect("/maintenance");
   }
 
+  const [schoolName, logoUrl, showLogo, socialYoutube, socialVk, socialTelegram, orgRequisites] =
+    await Promise.all([
+      getSetting("schoolName"),
+      getSetting("logoUrl"),
+      getSetting("showLogo"),
+      getSetting("socialYoutube"),
+      getSetting("socialVk"),
+      getSetting("socialTelegram"),
+      getSetting("orgRequisites"),
+    ]);
+
   const isImpersonating = !!(session.session as { impersonatedBy?: string }).impersonatedBy;
 
   return (
@@ -25,8 +36,12 @@ export default async function StudentLayout({ children }: { children: React.Reac
         className="sticky top-0 z-10 flex items-center justify-between px-6 py-3"
         style={{ borderBottom: "2px solid var(--border)", backgroundColor: "var(--background)" }}
       >
-        <Link href="/dashboard" className="font-bold tracking-wide" style={{ color: "var(--foreground)" }}>
-          Second Brain
+        <Link href="/dashboard" className="flex items-center gap-2 font-bold tracking-wide" style={{ color: "var(--foreground)" }}>
+          {logoUrl && showLogo === "true" && (
+            // eslint-disable-next-line @next/next/no-img-element
+            <img src={logoUrl} alt={schoolName} className="h-6 w-auto object-contain" />
+          )}
+          {schoolName}
         </Link>
         <div className="flex items-center gap-4">
           <span className="text-sm" style={{ color: "var(--muted-foreground)" }}>{session.user.name}</span>
@@ -34,6 +49,35 @@ export default async function StudentLayout({ children }: { children: React.Reac
         </div>
       </header>
       <div className="flex-1 flex flex-col">{children}</div>
+      {(socialYoutube || socialVk || socialTelegram || orgRequisites) && (
+        <footer
+          className="px-6 py-4 flex flex-col sm:flex-row items-center justify-between gap-3 text-xs"
+          style={{ borderTop: "2px solid var(--border)", color: "var(--muted-foreground)" }}
+        >
+          {orgRequisites && (
+            <p className="whitespace-pre-line text-center sm:text-left">{orgRequisites}</p>
+          )}
+          {(socialYoutube || socialVk || socialTelegram) && (
+            <div className="flex items-center gap-4 flex-shrink-0">
+              {socialYoutube && (
+                <a href={socialYoutube} target="_blank" rel="noopener noreferrer" className="hover:underline">
+                  YouTube
+                </a>
+              )}
+              {socialVk && (
+                <a href={socialVk} target="_blank" rel="noopener noreferrer" className="hover:underline">
+                  VK
+                </a>
+              )}
+              {socialTelegram && (
+                <a href={socialTelegram} target="_blank" rel="noopener noreferrer" className="hover:underline">
+                  Telegram
+                </a>
+              )}
+            </div>
+          )}
+        </footer>
+      )}
     </div>
   );
 }