fix: brainstorm infinite loop, ghost cursor, embedding ::vector cast, semantic search, billing stats, usage meter accordion

- Fix useBrainstormSocket: stable guestId via useRef, remove setState in cleanup
- Fix GhostCursor: direct DOM manipulation via refs, no useState re-renders
- Fix all SQL embedding queries: add ::vector cast on text columns
- Fix embedding truncation to 15000 chars (under 8192 token limit)
- Fix NoteEmbedding INSERT: remove non-existent updatedAt column
- Fix billing page: show all quota stats in grid instead of single metric
- Fix usage meter: accordion expand/collapse, per-feature detail
- Fix semantic search: rebuild 103 note embeddings, ::vector cast on vectorSearch
- Fix brainstorm expand/manual-idea/create: ::vector cast on embedding SQL

memento-note/app/(main)/settings/general/general-settings-client.tsx

@@ -7,7 +7,7 @@ import { toast } from 'sonner'
 import { useRouter } from 'next/navigation'
 import { Globe, Bell } from 'lucide-react'
 import { motion } from 'motion/react'
-import { PageEntry } from '@/components/page-entry'
+
 
 interface GeneralSettingsClientProps {
   initialSettings: {