feat: dashboard Second Brain, essai 7 jours et vérification e-mail

Rendre le dashboard actionnable (inbox, peek, carte mentale), aligner la facturation sur l’essai 7 jours, et bloquer le login e-mail tant que l’adresse n’est pas confirmée.

Co-authored-by: Cursor <cursoragent@cursor.com>

memento-note/lib/i18n/LanguageProvider.tsx

@@ -50,11 +50,16 @@ export function LanguageProvider({ children, initialLanguage = 'en', initialTran
 
   const isFirstRender = useRef(true)
 
-  // Load saved preference from localStorage AFTER hydration
+  // Load saved preference from cookie only (explicit picker). localStorage
+  // without cookie used to override note-based detection with a stale 'en'.
   useEffect(() => {
-    const saved = localStorage.getItem('user-language') as SupportedLanguage
-    if (saved && SUPPORTED_LANGS.includes(saved) && saved !== initialLanguage) {
-      setLanguageState(saved)
+    const cookie = document.cookie
+      .split(';')
+      .map(s => s.trim())
+      .find(s => s.startsWith('user-language='))
+      ?.split('=')[1] as SupportedLanguage | undefined
+    if (cookie && SUPPORTED_LANGS.includes(cookie) && cookie !== initialLanguage) {
+      setLanguageState(cookie)
     }
   }, [initialLanguage])