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 <noreply@anthropic.com>