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)/feed/page.tsx

@@ -1,19 +1,5 @@
-import type { Metadata } from "next";
-import { headers } from "next/headers";
-import { auth } from "@/lib/auth/server";
-import { db, userFollows, eq } from "@epicure/db";
-import { FeedPageContent } from "@/components/feed/feed-page-content";
+import { redirect } from "next/navigation";
 
-export const metadata: Metadata = {};
-
-export default async function FeedPage() {
-  const session = await auth.api.getSession({ headers: await headers() });
-  if (!session) return null;
-
-  const followedRows = await db
-    .select({ followingId: userFollows.followingId })
-    .from(userFollows)
-    .where(eq(userFollows.followerId, session.user.id));
-
-  return <FeedPageContent followedCount={followedRows.length} />;
+export default function FeedPage() {
+  redirect("/explore");
 }