fix: resolve React Error #310 and refactor admin section

- Fix React bug #33580: remove Suspense boundaries co-located with Link components
- Delete settings/loading.tsx and admin/loading.tsx (root cause of race condition)
- Convert all admin navigation from Next.js Link to anchor tags
- Move admin pages to dedicated (admin) route group
- Add AdminHeader matching main header visual design
- Add AdminSidebar with anchor-based navigation
- Add /api/admin/models route handler (replaces server actions for GET)
- Add /api/debug/client-error for server-side browser error reporting
- Add useNoteRefreshOptional() to fix crash in AdminHeader
- Hide Admin Dashboard menu for non-admin users
- Change app icons from yellow to blue (#3A7CA5) matching brand primary
- Fix admin search bar width to match main header

Made-with: Cursor

memento-note/components/error-reporter.tsx

@@ -0,0 +1,53 @@
+'use client'
+
+import { useEffect } from 'react'
+
+/**
+ * Captures unhandled client-side errors and forwards them to the server
+ * so they appear in `docker logs memento-web`. Loaded in the root layout.
+ */
+export function ErrorReporter() {
+  useEffect(() => {
+    function report(payload: object) {
+      fetch('/api/debug/client-error', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(payload),
+        keepalive: true,
+      }).catch(() => {})
+    }
+
+    function onError(event: ErrorEvent) {
+      report({
+        type: 'uncaught-error',
+        message: event.message,
+        filename: event.filename,
+        lineno: event.lineno,
+        colno: event.colno,
+        stack: event.error?.stack ?? null,
+        url: window.location.href,
+        timestamp: new Date().toISOString(),
+      })
+    }
+
+    function onUnhandledRejection(event: PromiseRejectionEvent) {
+      const reason = event.reason
+      report({
+        type: 'unhandled-rejection',
+        message: reason?.message ?? String(reason),
+        stack: reason?.stack ?? null,
+        url: window.location.href,
+        timestamp: new Date().toISOString(),
+      })
+    }
+
+    window.addEventListener('error', onError)
+    window.addEventListener('unhandledrejection', onUnhandledRejection)
+    return () => {
+      window.removeEventListener('error', onError)
+      window.removeEventListener('unhandledrejection', onUnhandledRejection)
+    }
+  }, [])
+
+  return null
+}