feat: locale-based generation, describe field for batch cooking; fix bulk-bar width and sourceUrl not saving

- AI recipe generation always used the app's own locale rather than a
  separate language picker — removed the picker, generation and the
  saved recipe's language now both follow useLocale() directly.
- Bulk-select action bar had an ungated max-w-md that capped it at 448px
  even past the sm: breakpoint where sm:w-auto was supposed to let it
  grow to content — added sm:max-w-none so desktop never scrolls.
- Batch-cooking generation had no free-text "describe" field like the
  standard recipe generator does — added one (BatchCookFields, both the
  standalone dialog and the AI dialog's batch tab), threaded through the
  API route and generateBatchCook's prompt as additional guidance.
- Recipes imported from a URL never actually got their sourceUrl
  persisted — CreateRecipeSchema didn't declare the field, so Zod
  silently stripped it before it ever reached the insert. The detail
  page's "Source: <hostname>" link already existed but was dead code
  for every real import until now.

Verified all 4 live: generate dialog has no language selector, batch
tab has a working describe textarea, bulk-select bar renders at full
content width with zero horizontal overflow on desktop, and a recipe
created with sourceUrl now round-trips and renders its source link.

apps/web/lib/ai/features/generate-batch-cook.ts

@@ -37,6 +37,7 @@ export async function generateBatchCook(
     servings?: number;
     dietaryPrefs?: string;
     difficulty?: "easy" | "medium" | "hard";
+    description?: string;
   },
   config?: AiConfig & { userContext?: string },
   locale?: string
@@ -59,6 +60,9 @@ export async function generateBatchCook(
   const difficultyClause = difficulty
     ? `Keep techniques at a ${difficulty} skill level.`
     : "";
+  const descriptionClause = options.description?.trim()
+    ? `Additional guidance: ${options.description.trim()}.`
+    : "";
 
   const systemPrompt = `You are a professional meal-prep chef writing ONE unified "batch cooking" recipe page — not several separate recipes. This mirrors real French batch-cooking guides: one shopping list, then a single prep session structured in two phases, covering multiple meals for the days ahead.
 
@@ -92,6 +96,7 @@ Write every description and instruction as plain prose — never use markdown fo
       `Design exactly ${totalDishes} distinct dishes, each for ${servings} servings.`,
       dietaryClause,
       difficultyClause,
+      descriptionClause,
     ].filter(Boolean).join(" "),
   });