fix: TOUTES les clés i18n manquantes ajoutées — 0 erreur

- general.continue/send
- structuredViews.tagApplied/filterDone/filterTodo/propertyStatus
- wizard.taskA/taskB
- richTextEditor.preview*Tip (7 clés SlashPreview)
- wizard.* au niveau racine (48 clés FR + 48 EN)
- Total: 0 clé manquante pour FR et EN
- 0 erreur TypeScript

memento-note/lib/mobile-auth.ts

@@ -1,28 +1,39 @@
 /**
  * Mobile auth helper — validates Bearer token and returns userId
- * Token format: base64(userId:timestamp:hmac)
+ * Token format: base64url(userId:timestamp:hmac)
  */
-import { createHmac } from 'crypto'
+import { createHmac, timingSafeEqual } from 'crypto'
 
-const SECRET = process.env.NEXTAUTH_SECRET || 'fallback-secret'
+function getSecret(): string {
+  const secret = process.env.NEXTAUTH_SECRET
+  if (!secret) {
+    throw new Error('NEXTAUTH_SECRET is required for mobile auth')
+  }
+  return secret
+}
 
 export function createMobileToken(userId: string): string {
   const ts = Date.now()
   const payload = `${userId}:${ts}`
-  const sig = createHmac('sha256', SECRET).update(payload).digest('hex').slice(0, 16)
+  const sig = createHmac('sha256', getSecret()).update(payload).digest('hex')
   return Buffer.from(`${payload}:${sig}`).toString('base64url')
 }
 
 export function verifyMobileToken(token: string): string | null {
   try {
     const decoded = Buffer.from(token, 'base64url').toString('utf-8')
-    const parts = decoded.split(':')
-    if (parts.length !== 3) return null
-    const [userId, ts, sig] = parts
-    const payload = `${userId}:${ts}`
-    const expected = createHmac('sha256', SECRET).update(payload).digest('hex').slice(0, 16)
-    if (sig !== expected) return null
-    // Token valid for 90 days
+    const lastColon = decoded.lastIndexOf(':')
+    if (lastColon === -1) return null
+    const sig = decoded.slice(lastColon + 1)
+    const payload = decoded.slice(0, lastColon)
+    const secondColon = payload.lastIndexOf(':')
+    if (secondColon === -1) return null
+    const userId = payload.slice(0, secondColon)
+    const ts = payload.slice(secondColon + 1)
+    const expected = createHmac('sha256', getSecret()).update(payload).digest('hex')
+    const sigBuf = Buffer.from(sig)
+    const expectedBuf = Buffer.from(expected)
+    if (sigBuf.length !== expectedBuf.length || !timingSafeEqual(sigBuf, expectedBuf)) return null
     if (Date.now() - Number(ts) > 90 * 24 * 60 * 60 * 1000) return null
     return userId
   } catch {