feat: dedicated favorites page for recipes

Favoriting already worked (heart toggle on the recipe detail page, DB
table, API route) but there was nowhere to see what you'd favorited —
the actual missing piece behind "add a favorites feature".

- New /recipes/favorites page: paginated grid of favorited recipes (cover
  photo, difficulty, time, author), sorted by most-recently favorited.
  A previously-favorited recipe stays visible even if the author later
  goes private, matching the existing private-accounts scope decision
  (existing access isn't revoked, only new discovery is affected).
- Unfavoriting from that page removes the card immediately — added an
  optional onToggle callback to FavoriteButton for this.
- Added a lightweight "My Recipes / Favorites" tab pair at the top of
  /recipes linking between the two, rather than a new top-level nav item
  (nav is already at 8 entries).

Deliberately out of scope: favorite toggles on the main recipe grid, feed
cards, or search/explore results — favoriting your own recipes is odd
UX, and wiring session-aware favorited state into the public
(unauthenticated) search route is a separate, bigger change.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/messages/fr.json

@@ -557,7 +557,12 @@
     "visibilityLabel": "Visibilité",
     "difficultyLabel": "Difficulté",
     "tagLabel": "Tag",
-    "clearFilters": "Effacer les filtres"
+    "clearFilters": "Effacer les filtres",
+    "tabMine": "Mes recettes",
+    "tabFavorites": "Favoris",
+    "favoritesCount": "{count} recette favorite",
+    "favoritesCountPlural": "{count} recettes favorites",
+    "favoritesEmpty": "Aucune recette favorite pour l'instant — touchez le cœur sur une recette pour l'enregistrer ici."
   },
   "recipeNotes": {
     "title": "Vos notes personnelles",