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/components/pantry/pantry-page-header.tsx

@@ -4,8 +4,12 @@ import Link from "next/link";
 import { ChefHat, Printer } from "lucide-react";
 import { buttonVariants } from "@/components/ui/button";
 import { cn } from "@/lib/utils";
+import { ExportMarkdownButton } from "@/components/shared/export-markdown-button";
+import { pantryToMarkdown } from "@/lib/markdown/pantry";
 
-export function PantryPageHeader() {
+type PantryItem = { rawName: string; quantity: string | null; unit: string | null; expiresAt: string | null };
+
+export function PantryPageHeader({ items }: { items: PantryItem[] }) {
   const t = useTranslations("pantry");
   const tCommon = useTranslations("common");
   return (
@@ -23,6 +27,7 @@ export function PantryPageHeader() {
           <Printer className="h-4 w-4" />
           {tCommon("print")}
         </a>
+        <ExportMarkdownButton markdown={pantryToMarkdown({ items })} filename="pantry" />
       </div>
     </div>
   );