feat: user blocking and content reporting/flagging

- user_blocks table (composite PK), Block/Unblock button on profiles.
  Blocking severs any existing follow relationship both ways and
  prevents the blocked party from following, commenting on the
  blocker's recipes, or the blocker from seeing their comments.
- reports table (recipe/comment/user targets, pending/reviewed/
  dismissed status). ReportButton on comments, admin review queue at
  /admin/reports with dismiss/mark-reviewed actions, audit-logged.

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

apps/web/app/api/v1/reports/route.ts

@@ -0,0 +1,45 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { db, reports, comments, recipes, users, eq } from "@epicure/db";
+import { requireSession } from "@/lib/api-auth";
+import { applyRateLimit } from "@/lib/rate-limit";
+import { randomUUID } from "crypto";
+
+const Schema = z.object({
+  targetType: z.enum(["recipe", "comment", "user"]),
+  targetId: z.string().min(1),
+  reason: z.string().min(1).max(1000),
+});
+
+export async function POST(req: NextRequest) {
+  const { session, response } = await requireSession();
+  if (response) return response;
+
+  const limited = await applyRateLimit(`rl:report:${session!.user.id}`, 10, 60);
+  if (limited) return limited;
+
+  const body = await req.json() as unknown;
+  const parsed = Schema.safeParse(body);
+  if (!parsed.success) return NextResponse.json({ error: "Validation error" }, { status: 400 });
+
+  const { targetType, targetId, reason } = parsed.data;
+
+  const exists =
+    targetType === "recipe"
+      ? await db.query.recipes.findFirst({ where: eq(recipes.id, targetId) })
+      : targetType === "comment"
+        ? await db.query.comments.findFirst({ where: eq(comments.id, targetId) })
+        : await db.query.users.findFirst({ where: eq(users.id, targetId) });
+
+  if (!exists) return NextResponse.json({ error: "Target not found" }, { status: 404 });
+
+  await db.insert(reports).values({
+    id: randomUUID(),
+    reporterId: session!.user.id,
+    targetType,
+    targetId,
+    reason,
+  });
+
+  return NextResponse.json({ ok: true }, { status: 201 });
+}