feat: usage quota visualization in AI settings

No user-facing view of AI-call/recipe/storage usage existed — only an
admin-only per-user panel. Adds the same numbers, with progress bars
against the user's actual tier limits (read fresh from the DB, not
the cached session), to Settings > AI.

v0.40.0

apps/web/messages/fr.json

@@ -325,6 +325,14 @@
     "nutrition": "Nutrition",
     "apiKeys": "Clés API",
     "webhooks": "Webhooks",
+    "usage": {
+      "title": "Utilisation ce mois-ci",
+      "description": "Réinitialisé au début de chaque mois ({month}).",
+      "aiCalls": "Appels IA",
+      "recipes": "Recettes créées",
+      "storage": "Stockage",
+      "unlimited": "Illimité"
+    },
     "byok": {
       "title": "Vos clés API (BYOK)",
       "description": "Utilisez vos propres clés API au lieu du quota partagé de l'application. Les clés sont chiffrées au repos."