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)/recipes/[id]/page.tsx

@@ -31,6 +31,8 @@ import { getPublicUrl } from "@/lib/storage";
 import { cn } from "@/lib/utils";
 import { RecipeChatPanel } from "@/components/recipe/recipe-chat-panel";
 import { KeepScreenAwake } from "@/components/recipe/keep-screen-awake";
+import { ExportMarkdownButton } from "@/components/shared/export-markdown-button";
+import { recipeToMarkdown } from "@/lib/markdown/recipe";
 import { getMessages, formatMessage } from "@/lib/i18n/server";
 
 type Params = { params: Promise<{ id: string }> };
@@ -172,6 +174,20 @@ export default async function RecipePage({ params }: Params) {
             />
             <ShareRecipeButton recipeId={id} visibility={recipe.visibility} />
             <PrintButton recipeId={id} />
+            <ExportMarkdownButton
+              markdown={recipeToMarkdown({
+                title: recipe.title,
+                description: recipe.description,
+                baseServings: recipe.baseServings,
+                prepMins: recipe.prepMins,
+                cookMins: recipe.cookMins,
+                difficulty: recipe.difficulty,
+                sourceUrl: recipe.sourceUrl,
+                ingredients: recipe.ingredients,
+                steps: recipe.steps,
+              })}
+              filename={recipe.title}
+            />
             {isOwner && (
               <>
                 <VersionHistoryButton