feat: manually create and edit batch-cook recipes

recipe-form.tsx previously had no batch-cook awareness at all — editing an
AI-generated batch-cook recipe and saving silently corrupted it (steps lost
their per-dish `appliesTo` tags, recipeBatchDishes rows went stale/orphaned,
since the create/update API schemas and edit-page query never touched them).

Adds a "batch-cook recipe" toggle to the form, an editable dish list (name,
description, fridge days, freezer-friendly/note, day-of instructions), and
per-step dish tagging (click a dish chip to mark which dish(es) that step
advances; empty = shared prep). Renaming a dish propagates to any step
still tagged with the old name instead of orphaning it. Wired through
Create/Update API schemas and the edit page's query/payload.

Verified locally: created a 2-dish batch recipe from scratch through the
real form, confirmed it renders identically to an AI-generated one (grouped
steps, dishes & storage cards), edited it, renamed a dish, reloaded, and
confirmed the step tag followed the rename rather than orphaning.

apps/web/messages/fr.json

@@ -648,7 +648,21 @@
     "discardChangesTitle": "Abandonner les modifications ?",
     "discardChangesDescription": "Vous avez des modifications non enregistrées. Si vous quittez maintenant, elles seront perdues.",
     "keepEditing": "Continuer l'édition",
-    "discardChanges": "Abandonner"
+    "discardChanges": "Abandonner",
+    "batchCookToggle": "Ceci est une recette de batch cooking",
+    "batchCookToggleHelp": "Divisez cette recette en plusieurs plats cuisinés ensemble, chacun avec ses propres consignes de conservation et de réchauffage.",
+    "dishes": "Plats",
+    "addDish": "Ajouter un plat",
+    "dishName": "Nom du plat",
+    "dishDescription": "Description",
+    "fridgeDays": "Frigo (jours)",
+    "freezerFriendly": "Se congèle bien",
+    "freezerNote": "Note de congélation",
+    "dayOfInstructions": "Consignes le jour J",
+    "dishesRequired": "Ajoutez au moins un plat",
+    "dayOfInstructionsRequired": "Chaque plat nécessite des consignes pour le jour J",
+    "appliesTo": "Concerne",
+    "sharedPrep": "Préparation commune"
   },
   "canCook": {
     "title": "Que puis-je cuisiner ?",