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/api/ai/reformulate/route.ts

@@ -2,6 +2,7 @@ import { NextRequest, NextResponse } from 'next/server'
 import { auth } from '@/auth'
 import { paragraphRefactorService } from '@/lib/ai/services/paragraph-refactor.service'
 import { getAISettings } from '@/app/actions/ai-settings'
+import { checkEntitlementOrThrow, QuotaExceededError, incrementUsageAsync } from '@/lib/entitlements'
 
 export async function POST(request: NextRequest) {
   try {
@@ -52,9 +53,27 @@ export async function POST(request: NextRequest) {
       }, { status: 400 })
     }
 
+    // Check quota
+    try {
+      await checkEntitlementOrThrow(session.user.id, 'reformulate')
+    } catch (err) {
+      if (err instanceof QuotaExceededError) {
+        const isTierLocked = err.currentQuota === 0
+        return NextResponse.json({
+          error: isTierLocked ? 'feature_locked' : 'quota_exceeded',
+          errorKey: isTierLocked ? 'ai.featureLocked' : 'ai.quotaExceeded',
+          upgradeTier: err.upgradeTier,
+          quotaExceeded: true,
+        }, { status: 402 })
+      }
+      throw err
+    }
+
     // Use the ParagraphRefactorService
     const result = await paragraphRefactorService.refactor(text, mode, format === 'html' ? 'html' : 'markdown', language)
 
+    incrementUsageAsync(session.user.id, 'reformulate')
+
     return NextResponse.json({
       originalText: result.original,
       reformulatedText: result.refactored,