feat: add batch-cooking sessions (single "mega recipe" with dish sections)

New AI-generated batch-cooking flow: pick N dinners/lunches + servings,
get one unified recipe covering a full prep session — merged shopping
list, steps tagged per-dish (a step can advance several dishes at once,
e.g. a shared oven bake), and per-dish storage (fridge/freezer) + exact
day-of reheat/finishing instructions.

Schema: recipes.isBatchCook, recipeSteps.appliesTo (dish names), new
recipeBatchDishes table. Batch recipes are excluded from the normal
/recipes list and live under their own /batch-cooking section.

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

apps/web/messages/fr.json

@@ -62,6 +62,12 @@
     "ingredients": "Ingrédients",
     "instructions": "Instructions",
     "photos": "Photos",
+    "batchCookBadge": "Batch cooking",
+    "batchCookPrep": "Préparation",
+    "batchCookDishesTitle": "Plats & conservation",
+    "batchCookFridgeDays": "Frigo : {days}j",
+    "batchCookFreezerFriendly": "Se congèle",
+    "batchCookDayOf": "Le jour J",
     "servings": "{count} portions",
     "prep": "{mins}m prép.",
     "cook": "{mins}m cuisson",
@@ -526,6 +532,25 @@
     "resendingSending": "Envoi en cours…",
     "or": "ou"
   },
+  "batchCooking": {
+    "title": "Batch cooking",
+    "subtitle": "Cuisinez une fois, mangez bien toute la semaine",
+    "empty": "Aucune session de batch cooking pour l'instant",
+    "newSession": "Nouvelle session de batch cooking",
+    "dishCount": "{count, plural, one {# plat} other {# plats}}",
+    "wizardTitle": "Planifier une session de batch cooking",
+    "wizardDescription": "Choisissez combien de repas couvrir — on génère une liste de courses partagée et une seule session de préparation pour tout.",
+    "dinners": "Dîners",
+    "lunches": "Déjeuners",
+    "servingsPerMeal": "Portions par repas",
+    "dietaryPrefs": "Préférences alimentaires",
+    "dietaryPrefsPlaceholder": "ex : végétarien, sans crustacés",
+    "anyDifficulty": "Peu importe",
+    "generate": "Générer",
+    "generating": "Génération… ça peut prendre une minute",
+    "generateSuccess": "Session de batch cooking créée",
+    "generateFailed": "Échec de la génération"
+  },
   "recipes": {
     "title": "Recettes",
     "subtitle": "Votre bibliothèque personnelle de recettes",
@@ -534,6 +559,7 @@
     "newSubtitle": "Créez votre recette depuis zéro",
     "importUrl": "Importer une URL",
     "generate": "Générer",
+    "batchCooking": "Batch cooking",
     "search": "Rechercher des recettes…",
     "noRecipes": "Aucune recette pour l'instant",
     "noMatch": "Aucune recette ne correspond",