feat: Cloudflare Turnstile on auth, CSP fixes, admin/SEO/analytics additions

Turnstile bot protection (sign-in, sign-up, password-reset):
- Register Better Auth's captcha plugin with the cloudflare-turnstile
  provider; endpoints listed explicitly rather than relying on defaults.
  /reset-password is intentionally excluded — it is reached only via a
  single-use emailed token.
- Add an explicit-render Turnstile widget component. Tokens are single-use,
  so each form resets the challenge after a failed submit; submit stays
  disabled until a token is held.
- Read the site key server-side and pass it down as a prop, so rotating it
  does not require a rebuild.
- Fail fast in production when TURNSTILE_SECRET_KEY is missing, and when a
  secret is set without a site key (that combination would demand a token
  no form can produce, locking every user out).
- Pass a throwaway secret during `next build` in the Dockerfile, mirroring
  the existing BETTER_AUTH_SECRET treatment, so image builds don't need it.

CSP fixes in middleware (these blocked Turnstile entirely):
- Add frame-src for challenges.cloudflare.com. Without it the widget's
  iframe fell back to default-src 'self' and was blocked outright.
- Allow 'unsafe-eval' and websockets in DEVELOPMENT only. `next dev`
  compiles with eval(), so the strict policy threw EvalError and killed
  hydration — no client JS ran at all, which also meant form submit
  handlers never fired. Production policy is unchanged and still strict.

Also included (concurrent work in the tree):
- Admin organizations pages and lib/admin/orgs.
- Episode moderation migration, SEO metadata (sitemap, robots, JSON-LD,
  OG/Twitter images, manifest), Umami analytics, not-found page.

Local dev database: docker-compose.dev.yml provisions Postgres 18 on port
5443 (5432-5442 are in use by other local projects).

Note: `npx tsc --noEmit` currently fails in app/(app)/team/page.tsx — an
`invitations` prop the component does not accept. This predates the commit
and will fail `next build` until fixed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/api/assets/[...key]/route.ts

@@ -33,15 +33,25 @@ export async function GET(
 
   // Resolve the owning episode from the asset record so we can authorize.
   const [audio, art] = await Promise.all([
-    prisma.audioAsset.findFirst({ where: { storageKey: key }, select: { episode: { select: { userId: true } } } }),
-    prisma.coverArt.findFirst({ where: { storageKey: key }, select: { episode: { select: { userId: true } } } }),
+    prisma.audioAsset.findFirst({
+      where: { storageKey: key },
+      select: { episode: { select: { userId: true, moderatedAt: true } } },
+    }),
+    prisma.coverArt.findFirst({
+      where: { storageKey: key },
+      select: { episode: { select: { userId: true, moderatedAt: true } } },
+    }),
   ]);
-  const ownerId = audio?.episode.userId ?? art?.episode.userId;
-  if (!ownerId) return new Response("Not found", { status: 404 });
+  const owningEpisode = audio?.episode ?? art?.episode;
+  if (!owningEpisode) return new Response("Not found", { status: 404 });
 
-  const isOwner = ownerId === session.user.id;
+  const isOwner = owningEpisode.userId === session.user.id;
   const isAdmin = session.user.role === "admin";
   if (!isOwner && !isAdmin) return new Response("Forbidden", { status: 403 });
+  // Admins keep access to removed media for appeals; the owner does not.
+  if (owningEpisode.moderatedAt && !isAdmin) {
+    return new Response("This episode was removed for a policy violation.", { status: 451 });
+  }
 
   // Stream off disk instead of buffering the whole file into memory.
   const total = await storage().size(key);

app/api/episodes/[id]/export/route.ts

@@ -3,6 +3,7 @@ import JSZip from "jszip";
 import { getServerSession } from "@/lib/auth/guards";
 import { prisma } from "@/lib/db";
 import { storage } from "@/lib/storage";
+import { rateLimit, LIMITS } from "@/lib/ratelimit";
 import type { StructuredScript } from "@/lib/ai/types";
 
 export const dynamic = "force-dynamic";
@@ -25,6 +26,16 @@ export async function GET(
   const session = await getServerSession();
   if (!session) return new Response("Unauthorized", { status: 401 });
 
+  // This handler buffers the full MP3 + cover into a JSZip in memory, so an
+  // authenticated user looping it is a cheap way to exhaust the heap.
+  const rl = await rateLimit("export", session.user.id, LIMITS.export);
+  if (!rl.ok) {
+    return new Response("Too many exports. Please slow down.", {
+      status: 429,
+      headers: { "Retry-After": String(rl.retryAfterSec ?? 60) },
+    });
+  }
+
   const episode = await prisma.episode.findUnique({
     where: { id },
     include: {
@@ -38,6 +49,11 @@ export async function GET(
   if (episode.userId !== session.user.id && session.user.role !== "admin") {
     return new Response("Forbidden", { status: 403 });
   }
+  // Removed content stays downloadable for admins (evidence/appeals) but not
+  // for the owner, who would otherwise just re-publish it elsewhere.
+  if (episode.moderatedAt && session.user.role !== "admin") {
+    return new Response("This episode was removed for a policy violation.", { status: 451 });
+  }
 
   const speakerNames: Record<string, string> = {};
   for (const s of episode.speakers) speakerNames[s.speakerKey] = s.displayName;

app/api/public/episodes/[shareId]/audio/route.ts

@@ -37,7 +37,9 @@ export async function GET(
   const { shareId } = await params;
 
   const episode = await prisma.episode.findUnique({
-    where: { shareId },
+    // A removed episode must be unreachable even if a share link is still
+    // circulating; moderatedAt is the takedown marker.
+    where: { shareId, moderatedAt: null },
     select: { audioAsset: { select: { storageKey: true } } },
   });
   const key = episode?.audioAsset?.storageKey;

app/api/public/episodes/[shareId]/cover/route.ts

@@ -42,7 +42,9 @@ export async function GET(
   const { shareId } = await params;
 
   const episode = await prisma.episode.findUnique({
-    where: { shareId },
+    // A removed episode must be unreachable even if a share link is still
+    // circulating; moderatedAt is the takedown marker.
+    where: { shareId, moderatedAt: null },
     select: { coverArt: { select: { storageKey: true } } },
   });
   const key = episode?.coverArt?.storageKey;

app/api/v1/episodes/route.ts

@@ -2,7 +2,7 @@ import { NextRequest } from "next/server";
 import { z } from "zod";
 import { verifyApiKey, bearerKey } from "@/lib/apikeys";
 import { prisma } from "@/lib/db";
-import { getEffectivePlan } from "@/lib/billing/subscription";
+import { getEffectivePlan, subjectHasFeature } from "@/lib/billing/subscription";
 import { reserveLimit, LimitExceededError } from "@/lib/usage/limits";
 import { refundUsage } from "@/lib/usage/meter";
 import { enqueueEpisodeGeneration } from "@/lib/queue/pgboss";
@@ -19,11 +19,30 @@ async function authorize(req: NextRequest) {
   return verifyApiKey(bearerKey(req.headers.get("authorization")));
 }
 
+/**
+ * Re-check the `api_access` entitlement on every request.
+ *
+ * Key CREATION gates on this feature, but a key outlives the subscription that
+ * minted it: without this check a user could subscribe, mint a key, downgrade to
+ * Free, and keep programmatic access to a paid feature indefinitely.
+ * Returns a 402 Response when the entitlement is gone, else null.
+ */
+async function requireApiAccess(userId: string): Promise<Response | null> {
+  if (await subjectHasFeature(userId, "api_access")) return null;
+  return Response.json(
+    { error: "API access requires an active Pro or Agency plan." },
+    { status: 402 }
+  );
+}
+
 /** GET /api/v1/episodes — list the caller's episodes. */
 export async function GET(req: NextRequest) {
   const auth = await authorize(req);
   if (!auth) return Response.json({ error: "Invalid API key" }, { status: 401 });
 
+  const denied = await requireApiAccess(auth.userId);
+  if (denied) return denied;
+
   const rl = await rateLimit("read", auth.userId, LIMITS.read);
   if (!rl.ok) {
     return Response.json(
@@ -56,6 +75,9 @@ export async function POST(req: NextRequest) {
   const auth = await authorize(req);
   if (!auth) return Response.json({ error: "Invalid API key" }, { status: 401 });
 
+  const denied = await requireApiAccess(auth.userId);
+  if (denied) return denied;
+
   const rl = await rateLimit("api", auth.userId, LIMITS.api);
   if (!rl.ok) {
     return Response.json(

app/api/webhooks/paypal/route.ts

@@ -2,9 +2,20 @@ import { NextRequest } from "next/server";
 import { verifyPaypalWebhook } from "@/lib/billing/paypal";
 import { handlePaypalEvent } from "@/lib/billing/webhooks/paypal";
 import { alreadyProcessed, logWebhook } from "@/lib/billing/webhook-log";
+import { rateLimit, LIMITS } from "@/lib/ratelimit";
 
 export const dynamic = "force-dynamic";
 
+/** Best-effort client IP for anonymous rate limiting. */
+function clientKey(req: NextRequest): string {
+  const fwd = req.headers.get("x-forwarded-for");
+  if (fwd) return fwd.split(",")[0].trim();
+  return req.headers.get("x-real-ip") ?? "anon";
+}
+
+// PayPal webhook bodies are small; anything larger is not a real event.
+const MAX_BODY_BYTES = 1_000_000;
+
 const SIG_HEADERS = [
   "paypal-auth-algo",
   "paypal-cert-url",
@@ -14,9 +25,44 @@ const SIG_HEADERS = [
 ];
 
 export async function POST(req: NextRequest) {
-  const body = await req.text();
+  // This endpoint is unauthenticated and verification is done by CALLING PayPal,
+  // so every request costs us an outbound API call. Throttle per IP, and reject
+  // obviously-bogus requests before spending anything.
+  const rl = await rateLimit("paypal-webhook", clientKey(req), LIMITS.webhook);
+  if (!rl.ok) {
+    return new Response("Too many requests", {
+      status: 429,
+      headers: { "Retry-After": String(rl.retryAfterSec ?? 60) },
+    });
+  }
+
   const headers: Record<string, string | undefined> = {};
   for (const h of SIG_HEADERS) headers[h] = req.headers.get(h) ?? undefined;
+  // A genuine PayPal delivery always carries all five signature headers. Bailing
+  // here costs nothing, whereas verifyPaypalWebhook() would hit the network.
+  if (SIG_HEADERS.some((h) => !headers[h])) {
+    return new Response("Invalid signature", { status: 400 });
+  }
+
+  // Check the declared size BEFORE reading, so an oversized body is never
+  // materialized in memory. The post-read check still backstops a missing or
+  // lying Content-Length.
+  const declared = Number(req.headers.get("content-length") ?? "0");
+  if (Number.isFinite(declared) && declared > MAX_BODY_BYTES) {
+    return new Response("Payload too large", { status: 413 });
+  }
+
+  const body = await req.text();
+  if (body.length > MAX_BODY_BYTES) {
+    return new Response("Payload too large", { status: 413 });
+  }
+
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(body);
+  } catch {
+    return new Response("Invalid payload", { status: 400 });
+  }
 
   const verified = await verifyPaypalWebhook(headers, body).catch(() => false);
   if (!verified) {
@@ -24,7 +70,7 @@ export async function POST(req: NextRequest) {
     return new Response("Invalid signature", { status: 400 });
   }
 
-  const event = JSON.parse(body) as { id?: string; event_type?: string };
+  const event = parsed as { id?: string; event_type?: string };
   const eventId = event.id ?? `paypal_${Date.now()}`;
   if (event.id && (await alreadyProcessed(eventId))) return new Response("ok (duplicate)");