feat: merge Explore and Activity Feed, unify recipe cards

Explore and Feed covered overlapping ground (recommendations, following,
trending) in two separate places with three different card designs.
Explore now hosts Discover/Following/For You tabs, and every recipe
card everywhere on the page matches the Recipes page's cover-photo
card instead of the old text-only search result.

v0.36.0

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

@@ -1,9 +1,11 @@
 import type { Metadata } from "next";
+import { headers } from "next/headers";
 import {
   db,
   recipes,
   users,
   favorites,
+  userFollows,
   eq,
   desc,
   sql,
@@ -11,20 +13,29 @@ import {
   gte,
   count,
 } from "@epicure/db";
+import { auth } from "@/lib/auth/server";
 import { ExplorePageContent } from "@/components/search/explore-page-content";
-import { getAvgRatingsByRecipeId } from "@/lib/recipe-ratings";
+import { attachCardExtras } from "@/lib/recipe-card-extras";
 
 export const metadata: Metadata = {};
 
 export type RecipeResult = {
   id: string;
   title: string;
+  description: string | null;
   authorName: string | null;
-  difficulty: string | null;
+  difficulty: "easy" | "medium" | "hard" | null;
+  baseServings: number;
   prepMins: number | null;
   cookMins: number | null;
-  avgRating: number | null;
-  ratingCount: number;
+  visibility: "private" | "unlisted" | "public";
+  tags: string[];
+  isBatchCook: boolean;
+  sourceUrl: string | null;
+  recipeType: "dish" | "drink";
+  photos: { storageKey: string; isCover: boolean }[];
+  dishCount: number;
+  isFavorited: boolean;
 };
 
 export default async function ExplorePage({
@@ -33,19 +44,28 @@ export default async function ExplorePage({
   searchParams: Promise<{ q?: string }>;
 }) {
   const { q } = await searchParams;
+  const session = await auth.api.getSession({ headers: await headers() });
   const sevenDaysAgo = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000);
 
+  const columns = {
+    id: recipes.id,
+    title: recipes.title,
+    description: recipes.description,
+    authorName: users.name,
+    difficulty: recipes.difficulty,
+    baseServings: recipes.baseServings,
+    prepMins: recipes.prepMins,
+    cookMins: recipes.cookMins,
+    visibility: recipes.visibility,
+    tags: recipes.tags,
+    isBatchCook: recipes.isBatchCook,
+    sourceUrl: recipes.sourceUrl,
+    recipeType: recipes.recipeType,
+  };
+
   // Trending: public recipes ordered by favorite count in last 7 days
   const trendingRows = await db
-    .select({
-      id: recipes.id,
-      title: recipes.title,
-      authorName: users.name,
-      difficulty: recipes.difficulty,
-      prepMins: recipes.prepMins,
-      cookMins: recipes.cookMins,
-      favoriteCount: count(favorites.recipeId),
-    })
+    .select({ ...columns, favoriteCount: count(favorites.recipeId) })
     .from(recipes)
     .innerJoin(users, eq(recipes.authorId, users.id))
     .leftJoin(
@@ -62,31 +82,17 @@ export default async function ExplorePage({
 
   // Recent: public recipes ordered by createdAt desc
   const recentRows = await db
-    .select({
-      id: recipes.id,
-      title: recipes.title,
-      authorName: users.name,
-      difficulty: recipes.difficulty,
-      prepMins: recipes.prepMins,
-      cookMins: recipes.cookMins,
-    })
+    .select(columns)
     .from(recipes)
     .innerJoin(users, eq(recipes.authorId, users.id))
     .where(and(eq(recipes.visibility, "public"), eq(users.isPrivate, false)))
     .orderBy(desc(recipes.createdAt))
     .limit(12);
 
-  const ratingByRecipe = await getAvgRatingsByRecipeId([
-    ...trendingRows.map((r) => r.id),
-    ...recentRows.map((r) => r.id),
+  const [trending, recent] = await Promise.all([
+    attachCardExtras(trendingRows.map(({ favoriteCount: _fc, ...r }) => r), session?.user.id),
+    attachCardExtras(recentRows, session?.user.id),
   ]);
-  const withRating = (r: { id: string }) => ({
-    avgRating: ratingByRecipe.get(r.id)?.avgRating ?? null,
-    ratingCount: ratingByRecipe.get(r.id)?.ratingCount ?? 0,
-  });
-
-  const trending: RecipeResult[] = trendingRows.map(({ favoriteCount: _fc, ...r }) => ({ ...r, ...withRating(r) }));
-  const recent: RecipeResult[] = recentRows.map((r) => ({ ...r, ...withRating(r) }));
 
   // 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.
@@ -102,12 +108,22 @@ export default async function ExplorePage({
   `);
   const popularTags = popularTagsResult.map((r) => r.tag);
 
+  const followedCount = session
+    ? (
+        await db
+          .select({ followingId: userFollows.followingId })
+          .from(userFollows)
+          .where(eq(userFollows.followerId, session.user.id))
+      ).length
+    : 0;
+
   return (
     <ExplorePageContent
       trending={trending}
       recent={recent}
       initialQuery={q ?? ""}
       popularTags={popularTags}
+      followedCount={followedCount}
     />
   );
 }