feat: surface pantry-expiry recipe suggestions

Pantry page now shows a "Use it up soon" widget with recipes that use
soon-to-expire pantry items, across the user's own recipes plus public/
unlisted ones (the existing /recipes/can-cook page only looked at the
user's own). Extracted the matching/scoring logic shared by both into
lib/pantry-match.ts.

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

apps/web/messages/en.json

@@ -622,6 +622,8 @@
     "title": "Pantry",
     "subtitle": "Track what you have on hand",
     "canCook": "What can I cook?",
+    "expiringSoonSuggestionsTitle": "Use it up soon",
+    "seeAll": "See all",
     "itemNamePlaceholder": "Item name",
     "qtyPlaceholder": "Qty",
     "unitPlaceholder": "Unit",