feat: copy/export as Markdown wherever print exists

Added a shared ExportMarkdownButton (copy to clipboard / download .md)
next to every existing print button: recipe, shopping list,
collection, meal plan, pantry. Each surface gets a small serializer in
lib/markdown/ built from data already in scope at that page — no new
queries except pantry, where items now thread through as a prop to
PantryPageHeader instead of being fetched only for PantryManager.

Also fixes an unrelated bug hit while verifying the collection export:
RecipeCard called the client-only useTranslations() hook without
"use client", so it rendered fine everywhere it happened to run inside
an already-client tree but 500'd — "Couldn't find next-intl config
file" — when Next tried to run it as a Server Component, which only
happens on the collection detail page (its only caller). Collections
with recipes in them were completely broken.

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

apps/web/app/(app)/collections/[id]/page.tsx

@@ -10,6 +10,8 @@ import { ForkCollectionButton } from "@/components/collections/fork-collection-b
 import { ShareCollectionButton } from "@/components/collections/share-collection-button";
 import { buttonVariants } from "@/components/ui/button";
 import { cn } from "@/lib/utils";
+import { ExportMarkdownButton } from "@/components/shared/export-markdown-button";
+import { collectionToMarkdown } from "@/lib/markdown/collection";
 import { getMessages } from "@/lib/i18n/server";
 
 type Params = { params: Promise<{ id: string }> };
@@ -46,10 +48,20 @@ export default async function CollectionPage({ params }: Params) {
         </div>
         <div className="flex flex-wrap items-center gap-2">
           {col.recipes.length > 0 && (
-            <Link href={`/print/collection/${id}`} target="_blank" className={cn(buttonVariants({ variant: "outline", size: "sm" }))}>
-              <Printer className="h-4 w-4" />
-              {m.collections.exportPdf}
-            </Link>
+            <>
+              <Link href={`/print/collection/${id}`} target="_blank" className={cn(buttonVariants({ variant: "outline", size: "sm" }))}>
+                <Printer className="h-4 w-4" />
+                {m.collections.exportPdf}
+              </Link>
+              <ExportMarkdownButton
+                markdown={collectionToMarkdown({
+                  name: col.name,
+                  description: col.description,
+                  recipes: col.recipes.flatMap((r) => (r.recipe ? [r.recipe] : [])),
+                })}
+                filename={col.name}
+              />
+            </>
           )}
           {isOwner && <ShareCollectionButton collectionId={id} />}
           {!isOwner && col.isPublic && (