fix(og): map 'foreign beer' category to international-beer API endpoint

The OG preview handler derives the API endpoint name directly from the
URL's category param. For foreign beer drinks the category field value
is 'foreign beer' (with a space) but the API endpoint is
'international-beer', so the handler fetched a non-existent URL and
silently fell back to the plain SPA — no OG metadata was injected.

Add a CATEGORY_TO_ENDPOINT lookup in fetchDrinkData so 'foreign beer'
resolves to 'international-beer.json', matching what the Flutter app
uses when loading these drinks.

Author: claude

functions/_lib/drink-preview.js

@@ -12,6 +12,11 @@ const CRAWLER_UA_PATTERNS = [
 const DATA_BASE_URL = 'https://data.cambeerfestival.app';
 const OG_IMAGE_URL = 'https://cambeerfestival.app/icons/Icon-512.png';
 
+// Product category field values don't always match their API endpoint names.
+const CATEGORY_TO_ENDPOINT = {
+  'foreign beer': 'international-beer',
+};
+
 export function isCrawler(userAgent) {
   if (!userAgent) return false;
   const ua = userAgent.toLowerCase();
@@ -59,7 +64,8 @@ export function buildOgTags(product, producer, canonicalUrl) {
 }
 
 export async function fetchDrinkData(festivalId, category) {
-  const url = `${DATA_BASE_URL}/${encodeURIComponent(festivalId)}/${encodeURIComponent(category)}.json`;
+  const endpoint = CATEGORY_TO_ENDPOINT[category] ?? category;
+  const url = `${DATA_BASE_URL}/${encodeURIComponent(festivalId)}/${encodeURIComponent(endpoint)}.json`;
   const response = await fetch(url);
   if (!response.ok) return null;
   const data = await response.json();

functions/test/drink-preview.test.js

@@ -263,5 +263,17 @@ describe('fetchDrinkData', () => {
       'https://data.cambeerfestival.app/cbf2025/beer.json',
     );
   });
+
+  it('maps "foreign beer" category to "international-beer" endpoint', async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      ok: true,
+      json: () => Promise.resolve({ producers: [] }),
+    });
+    vi.stubGlobal('fetch', mockFetch);
+    await fetchDrinkData('cbf2026', 'foreign beer');
+    expect(mockFetch).toHaveBeenCalledWith(
+      'https://data.cambeerfestival.app/cbf2026/international-beer.json',
+    );
+  });
 });