fix(panels): bypass GoTrueClient lock — expose accessToken via AuthContext, gate panels on auth

Root cause: apiFetch called supabase.auth.getSession() on every API request, acquiring
the GoTrueClient internal lock. On refresh, concurrent mount of panels caused lock
contention — the loadCabinets/loadSessions fetch awaits hung, loading spinner never
cleared.

- AuthContext: add accessToken state, set/clear it alongside user on all auth events
- CCFilesPanel: apiFetch reads accessToken from AuthContext (no lock), loadCabinets
  effect gated on authUser.id (fires only after SIGNED_IN, session guaranteed valid)
- CCTranscriptionPanel: loadSessions effect gated on authUser.id for same reason

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/utils/tldraw/ui-overrides/components/shared/CCFilesPanel.tsx

@@ -40,7 +40,7 @@ import ImageIcon from '@mui/icons-material/Image';
 import DescriptionIcon from '@mui/icons-material/Description';
 import InsertDriveFileIcon from '@mui/icons-material/InsertDriveFile';
 import { useTLDraw } from '../../../../../contexts/TLDrawContext';
-import { supabase } from '../../../../../supabaseClient';
+import { useAuth } from '../../../../../contexts/AuthContext';
 import { useNavigate } from 'react-router-dom';
 import {
   calculateDirectoryStats,
@@ -92,7 +92,8 @@ interface FileListResponse {
 }
 
 export const CCFilesPanel: React.FC = () => {
-  const { tldrawPreferences, authToken } = useTLDraw() as { tldrawPreferences?: { colorScheme?: 'light' | 'dark' | 'system' }, authToken?: string };
+  const { tldrawPreferences } = useTLDraw() as { tldrawPreferences?: { colorScheme?: 'light' | 'dark' | 'system' } };
+  const { user: authUser, accessToken } = useAuth();
   const prefersDarkMode = useMediaQuery('(prefers-color-scheme: dark)');
   const [cabinets, setCabinets] = useState<Cabinet[]>([]);
   const [selectedCabinet, setSelectedCabinet] = useState<string>('');
@@ -144,14 +145,14 @@ export const CCFilesPanel: React.FC = () => {
 
   const apiFetch = useCallback(async (url: string, init?: RequestInitLike) => {
     const headers: HeadersInitLike = {
-      'Authorization': `Bearer ${(await supabase.auth.getSession()).data.session?.access_token || authToken || ''}`,
+      'Authorization': `Bearer ${accessToken || ''}`,
       ...(init?.headers || {})
     };
     const fullUrl = url.startsWith('http') ? url : `${API_BASE}${url}`;
     const res = await fetch(fullUrl, { ...(init || {}), headers });
     if (!res.ok) throw new Error(await res.text());
     return res.json();
-  }, [authToken, API_BASE]);
+  }, [accessToken, API_BASE]);
 
   const loadCabinets = useCallback(async () => {
     setLoading(true);
@@ -207,8 +208,11 @@ export const CCFilesPanel: React.FC = () => {
   }, [currentPage, itemsPerPage, sortBy, sortOrder, searchTerm, apiFetch, currentDirectoryId]);
 
   useEffect(() => {
-    loadCabinets();
-  }, [loadCabinets]);
+    if (authUser?.id) {
+      initialSelectionDone.current = false;
+      loadCabinets();
+    }
+  }, [loadCabinets, authUser?.id]);
 
   // Main loading effect - handles pagination, sorting, cabinet changes, directory navigation
   useEffect(() => {