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/app/api/v1/ai/batch-cook/generate/route.ts

@@ -15,6 +15,7 @@ const Schema = z.object({
   servings: z.number().int().min(1).max(12).default(4),
   dietaryPrefs: z.string().max(200).optional(),
   difficulty: z.enum(["easy", "medium", "hard"]).optional(),
+  description: z.string().max(500).optional(),
 });
 
 export async function POST(req: NextRequest) {
@@ -50,6 +51,7 @@ export async function POST(req: NextRequest) {
         servings: parsed.data.servings,
         dietaryPrefs: parsed.data.dietaryPrefs,
         difficulty: parsed.data.difficulty,
+        description: parsed.data.description,
       },
       { ...config, userContext: privateBio ?? undefined },
       locale