feat: design system overhaul — sidebar, AI chats, settings, brainstorm, color cleanup

- Sidebar: dynamic brand-accent colors, brainstorm section restyled
- AI chat general: popup panel with expand/collapse, hides when contextual AI open
- AI chat contextual: tabs reordered (Actions first), X close button, height fix
- Settings: all tabs restyled, 6 new color presets (sage, terracotta, iron, etc.)
- Global color cleanup: emerald/orange hardcoded → brand-accent dynamic
- Brainstorm page: orange → brand-accent throughout
- PageEntry animation component added to key pages
- Floating AI button: bg-brand-accent instead of hardcoded black
- i18n: all 15 locales updated with new AI/billing keys
- Billing: freemium quota tracking, BYOK, stripe subscription scaffolding
- Admin: integrated into new design
- AGENTS.md + CLAUDE.md project rules added

memento-note/app/api/brainstorm/[sessionId]/expand/route.ts

@@ -2,10 +2,15 @@ import { NextRequest, NextResponse } from 'next/server'
 import prisma from '@/lib/prisma'
 import { auth } from '@/auth'
 import { z } from 'zod'
-import { getTagsProvider } from '@/lib/ai/factory'
+import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-for-user'
 import { getSystemConfig } from '@/lib/config'
 import { embeddingService } from '@/lib/ai/services/embedding.service'
 import {
+  checkSessionEntitlementOrThrow,
+  QuotaExceededError,
+} from '@/lib/entitlements'
+import {
+  billingOwnerFromSession,
   verifyParticipant,
   resolveAiContextUserId,
   sanitizeNotesForGuest,
@@ -182,7 +187,23 @@ export async function POST(
       return NextResponse.json({ error: 'Session not found' }, { status: 404 })
     }
 
-    const parentIdea = brainstormSession.ideas.find(i => i.id === ideaId)
+    const { billingOwnerId, isGuestActor } = billingOwnerFromSession(
+      brainstormSession.userId,
+      session.user.id,
+    )
+    // Story 3.5: per-provider BYOK bypass
+    const earlyConfig = await getSystemConfig()
+    const { usedByok: willUseByok } = await willUseByokForLane('tags', earlyConfig, billingOwnerId)
+    if (!willUseByok) {
+      await checkSessionEntitlementOrThrow(
+        billingOwnerId,
+        session.user.id,
+        isGuestActor,
+        'brainstorm_expand',
+      )
+    }
+
+    const parentIdea = (brainstormSession.ideas || []).find(i => i.id === ideaId)
     if (!parentIdea) {
       return NextResponse.json({ error: 'Idea not found' }, { status: 404 })
     }
@@ -205,7 +226,6 @@ export async function POST(
     }
 
     const config = await getSystemConfig()
-    const provider = getTagsProvider(config)
 
     const prompt = buildExpandPromptV2(
       parentIdea.title,
@@ -216,7 +236,12 @@ export async function POST(
       locale
     )
 
-    const llmResponse = await provider.generateText(prompt)
+    const { result: llmResponse } = await runLaneWithBillingUser(
+      'tags',
+      config,
+      billingOwnerId,
+      (provider) => provider.generateText(prompt),
+    )
 
     let newIdeas: any[]
     try {
@@ -311,6 +336,9 @@ export async function POST(
 
     return NextResponse.json({ success: true, data: updatedSession })
   } catch (error: any) {
+    if (error instanceof QuotaExceededError) {
+      return NextResponse.json(error.toJSON(), { status: 402 })
+    }
     if (error instanceof z.ZodError) {
       return NextResponse.json({ error: error.issues }, { status: 400 })
     }

memento-note/app/api/brainstorm/[sessionId]/manual-idea/route.ts

@@ -2,10 +2,20 @@ import { NextRequest, NextResponse } from 'next/server'
 import prisma from '@/lib/prisma'
 import { auth } from '@/auth'
 import { z } from 'zod'
-import { verifyParticipant, logActivity, resolveAiContextUserId, captureSnapshot } from '@/lib/brainstorm-collab'
+import {
+  billingOwnerFromSession,
+  verifyParticipant,
+  logActivity,
+  resolveAiContextUserId,
+  captureSnapshot,
+} from '@/lib/brainstorm-collab'
 import { embeddingService } from '@/lib/ai/services/embedding.service'
-import { getTagsProvider } from '@/lib/ai/factory'
+import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-for-user'
 import { getSystemConfig } from '@/lib/config'
+import {
+  reserveUsageOrThrow,
+  QuotaExceededError,
+} from '@/lib/entitlements'
 import { emitToSession } from '@/lib/socket-emit'
 
 const manualSchema = z.object({
@@ -43,6 +53,11 @@ export async function POST(
       return NextResponse.json({ error: 'Session not found' }, { status: 404 })
     }
 
+    const { billingOwnerId, isGuestActor } = billingOwnerFromSession(
+      brainstormSession.userId,
+      session.user.id,
+    )
+
     let wave = 1
     let parentIdea: any = null
     if (parentIdeaId) {
@@ -78,8 +93,25 @@ export async function POST(
       },
     })
 
-    // [UPDATE - SÉCURITÉ] Recherche vectorielle guest-safe
+    // Story 3.5: per-provider BYOK bypass for enrich
+    let enrichBlocked = false
+    try {
+      const config = await getSystemConfig()
+      const { usedByok: willUseByok } = await willUseByokForLane('tags', config, billingOwnerId)
+      if (!willUseByok) {
+        await reserveUsageOrThrow(billingOwnerId, 'brainstorm_enrich')
+      }
+    } catch (err) {
+      if (err instanceof QuotaExceededError) {
+        enrichBlocked = true
+      } else {
+        console.error('[manual-idea] reserveUsage error:', err)
+      }
+    }
+
+    // [UPDATE - SÉCURITÉ] Recherche vectorielle guest-safe (skipped when host quota exhausted)
     let relatedNoteIds: string[] = []
+    if (!enrichBlocked) {
     try {
       const { isGuest, publicNoteIds, aiUserId } = await resolveAiContextUserId(sessionId, session.user.id)
 
@@ -117,7 +149,10 @@ export async function POST(
         }
         relatedNoteIds = results.map((r: any) => r.id)
       }
-    } catch {}
+    } catch (vectorErr) {
+      console.error('[manual-idea] vector context search failed:', vectorErr)
+    }
+    }
 
     if (relatedNoteIds.length > 0) {
       const notes = await prisma.note.findMany({
@@ -155,6 +190,16 @@ export async function POST(
     const requestingUserId = session.user!.id
 
     const enrichAsync = async () => {
+      if (enrichBlocked) {
+        await emitToSession(sessionId, 'idea:ai_failed', {
+          ideaId: idea.id,
+          reason: 'quota_exceeded',
+          isGuestActor,
+          billingOwnerId,
+        })
+        return
+      }
+
       try {
         // Notifier le room que l'IA traite ce nœud (bordure pulsante violet)
         await emitToSession(sessionId, 'idea:ai_processing', {
@@ -163,7 +208,6 @@ export async function POST(
         })
 
         const config = await getSystemConfig()
-        const provider = getTagsProvider(config)
         const lang = locale === 'fr' ? 'French' : locale === 'es' ? 'Spanish' : locale === 'de' ? 'German' : locale === 'it' ? 'Italian' : locale === 'pt' ? 'Portuguese' : locale === 'ja' ? 'Japanese' : locale === 'ko' ? 'Korean' : locale === 'zh' ? 'Chinese' : locale === 'ar' ? 'Arabic' : "the user's language"
 
         const enrichPrompt = `You are an idea enrichment assistant. Given a user's raw brainstorm idea and context, produce a JSON object with:
@@ -181,7 +225,12 @@ User's raw description: "${description || 'none provided'}"
 
 Respond ONLY with the JSON object, no markdown.`
 
-        const raw = await provider.generateText(enrichPrompt)
+        const { result: raw } = await runLaneWithBillingUser(
+          'tags',
+          config,
+          billingOwnerId,
+          (provider) => provider.generateText(enrichPrompt),
+        )
         const cleaned = raw.replace(/```json\n?/g, '').replace(/```\n?/g, '').trim()
         const enriched = JSON.parse(cleaned)
 
@@ -195,7 +244,6 @@ Respond ONLY with the JSON object, no markdown.`
           data: { title: enrichedTitle, description: enrichedDescription, connectionToSeed, noveltyScore },
         })
 
-        // [UPDATE - TEMPS RÉEL] Notifier la complétion avec les données enrichies
         await emitToSession(sessionId, 'idea:ai_completed', {
           ideaId: idea.id,
           title: enrichedTitle,

memento-note/app/api/brainstorm/route.ts

@@ -2,9 +2,14 @@ import { NextRequest, NextResponse } from 'next/server'
 import prisma from '@/lib/prisma'
 import { auth } from '@/auth'
 import { z } from 'zod'
-import { getTagsProvider } from '@/lib/ai/factory'
+import { runLaneWithBillingUser, willUseByokForLane } from '@/lib/ai/provider-for-user'
 import { getSystemConfig } from '@/lib/config'
 import { embeddingService } from '@/lib/ai/services/embedding.service'
+import {
+  checkEntitlementOrThrow,
+  QuotaExceededError,
+  incrementUsageAsync,
+} from '@/lib/entitlements'
 import { logActivity, captureSnapshot } from '@/lib/brainstorm-collab'
 
 const waveSchema = z.object({
@@ -64,11 +69,7 @@ async function autoContextSearch(
     snippet: (n.content || '').slice(0, 300),
   }))
 
-  try {
-    const config = await getSystemConfig()
-    const provider = getTagsProvider(config)
-
-    const classifyPrompt = `Given the seed idea: "${seedIdea}"
+  const classifyPrompt = `Given the seed idea: "${seedIdea}"
 
 Classify each note as SUPPORT (confirms/reinforces the seed), TENSION (contradicts/questions the seed), or EXTENSION (extends the seed into an adjacent domain).
 
@@ -78,7 +79,14 @@ ${notesForLLM.map(n => `[${n.id}] "${n.title}": ${n.snippet}`).join('\n')}
 Respond ONLY with a valid JSON array of objects:
 { "noteId": string, "category": "SUPPORT" | "TENSION" | "EXTENSION" }`
 
-    const raw = await provider.generateText(classifyPrompt)
+  try {
+    const config = await getSystemConfig()
+    const { result: raw } = await runLaneWithBillingUser(
+      'tags',
+      config,
+      userId,
+      (provider) => provider.generateText(classifyPrompt),
+    )
     const cleaned = raw.replace(/```json\n?/g, '').replace(/```\n?/g, '').trim()
     const classifications: { noteId: string; category: 'SUPPORT' | 'TENSION' | 'EXTENSION' }[] = JSON.parse(cleaned)
 
@@ -199,13 +207,23 @@ export async function POST(request: NextRequest) {
     const body = await request.json()
     const { seedIdea, sourceNoteId, contextNoteIds, locale } = waveSchema.parse(body)
 
+    // Story 3.5: per-provider BYOK bypass
+    const config = await getSystemConfig()
+    const { usedByok: willUseByok } = await willUseByokForLane('tags', config, userId)
+    if (!willUseByok) {
+      await checkEntitlementOrThrow(userId, 'brainstorm_create')
+    }
+
     const classifiedNotes = await autoContextSearch(userId, seedIdea, contextNoteIds)
 
-    const config = await getSystemConfig()
-    const provider = getTagsProvider(config)
-
     const prompt = buildPromptV2(seedIdea, classifiedNotes, locale)
-    const llmResponse = await provider.generateText(prompt)
+    const { result: llmResponse, usedByok } = await runLaneWithBillingUser(
+      'tags',
+      config,
+      userId,
+      (provider) => provider.generateText(prompt),
+    )
+    if (!usedByok) incrementUsageAsync(userId, 'brainstorm_create')
 
     let ideas: any[]
     try {
@@ -312,6 +330,9 @@ export async function POST(request: NextRequest) {
       },
     }, { status: 201 })
   } catch (error: any) {
+    if (error instanceof QuotaExceededError) {
+      return NextResponse.json(error.toJSON(), { status: 402 })
+    }
     if (error instanceof z.ZodError) {
       return NextResponse.json({ error: error.issues }, { status: 400 })
     }