feat: search matches ingredients/tags, add tag filter chips to Explore

Search previously only matched title/description. Now also matches
ingredient rawName (EXISTS subquery) and tags (unnest+ILIKE) via
sequential scan — fine at current scale, flagged for a trigram/GIN
index if it gets slow. Explore also shows the 12 most-used public
tags as clickable chips that AND-filter results via a new `tags`
query param (array containment).

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

apps/web/app/(app)/explore/page.tsx

@@ -76,11 +76,26 @@ export default async function ExplorePage({
   const trending: RecipeResult[] = trendingRows.map(({ favoriteCount: _fc, ...r }) => r);
   const recent: RecipeResult[] = recentRows;
 
+  // Most-used tags across public recipes — shown as filter chips on the
+  // search bar so browsing by tag doesn't require typing the exact word.
+  const popularTagsResult = await db.execute<{ tag: string }>(sql`
+    select tag, count(*) as usage_count
+    from recipes r
+    inner join users u on r.author_id = u.id
+    cross join lateral unnest(r.tags) as tag
+    where r.visibility = 'public' and u.is_private = false
+    group by tag
+    order by usage_count desc
+    limit 12
+  `);
+  const popularTags = popularTagsResult.map((r) => r.tag);
+
   return (
     <ExplorePageContent
       trending={trending}
       recent={recent}
       initialQuery={q ?? ""}
+      popularTags={popularTags}
     />
   );
 }