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/actions/admin.ts

@@ -5,6 +5,7 @@ import prisma from '@/lib/prisma'
 import { auth } from '@/auth'
 import bcrypt from 'bcryptjs'
 import { z } from 'zod'
+import { SubscriptionTier, SubscriptionStatus } from '@prisma/client'
 
 // Schema pour la création d'utilisateur
 const CreateUserSchema = z.object({
@@ -33,6 +34,13 @@ export async function getUsers() {
         email: true,
         role: true,
         createdAt: true,
+        subscription: {
+          select: {
+            tier: true,
+            status: true,
+            currentPeriodEnd: true,
+          }
+        }
       }
     })
     return users
@@ -118,3 +126,39 @@ export async function updateUserRole(userId: string, newRole: string) {
     throw new Error('Failed to update role')
   }
 }
+
+export async function updateUserSubscription(userId: string, tier: string) {
+  await checkAdmin()
+
+  const validTiers: string[] = ['BASIC', 'PRO', 'BUSINESS', 'ENTERPRISE']
+  if (!validTiers.includes(tier)) {
+    throw new Error('Invalid tier')
+  }
+
+  try {
+    const now = new Date()
+    const periodEnd = new Date(now)
+    periodEnd.setFullYear(periodEnd.getFullYear() + 1)
+
+    await prisma.subscription.upsert({
+      where: { userId },
+      update: {
+        tier: tier as SubscriptionTier,
+        status: 'ACTIVE',
+        currentPeriodStart: now,
+        currentPeriodEnd: periodEnd,
+      },
+      create: {
+        userId,
+        tier: tier as SubscriptionTier,
+        status: 'ACTIVE' as SubscriptionStatus,
+        currentPeriodStart: now,
+        currentPeriodEnd: periodEnd,
+      },
+    })
+    revalidatePath('/admin')
+    return { success: true }
+  } catch (error) {
+    throw new Error('Failed to update subscription')
+  }
+}