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/components/recipe/recipes-grid.tsx

@@ -497,8 +497,8 @@ export function RecipesGrid({ recipes: initialRecipes }: { recipes: Recipe[] })
 
       {/* Floating bulk action bar */}
       {selectMode && selected.size > 0 && (
-        <div className="fixed bottom-4 sm:bottom-8 left-1/2 -translate-x-1/2 z-50 w-[calc(100vw-2rem)] max-w-md sm:w-auto animate-in slide-in-from-bottom-4 duration-200">
-          <div className="flex items-center gap-1 sm:gap-2 bg-popover border shadow-2xl rounded-2xl px-2 sm:px-5 py-2 sm:py-3 overflow-x-auto [scrollbar-width:none] [-ms-overflow-style:none] [&::-webkit-scrollbar]:hidden">
+        <div className="fixed bottom-4 sm:bottom-8 left-1/2 -translate-x-1/2 z-50 w-[calc(100vw-2rem)] sm:w-auto sm:max-w-none animate-in slide-in-from-bottom-4 duration-200">
+          <div className="flex items-center gap-1 sm:gap-2 bg-popover border shadow-2xl rounded-2xl px-2 sm:px-5 py-2 sm:py-3 overflow-x-auto sm:overflow-visible [scrollbar-width:none] [-ms-overflow-style:none] [&::-webkit-scrollbar]:hidden">
             <span className="text-sm font-semibold tabular-nums mr-1 shrink-0">{selected.size}</span>
             <div className="w-px h-5 bg-border mx-1 shrink-0" />
             <DropdownMenu>