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/layout.tsx

@@ -1,6 +1,9 @@
-import type { Metadata } from "next";
+import type { Metadata, Viewport } from "next";
 import { Wix_Madefor_Text, Wix_Madefor_Display } from "next/font/google";
 import { Toaster } from "sonner";
+import { UmamiAnalytics } from "@/components/analytics/umami";
+import { umamiConfig } from "@/lib/analytics";
+import { SITE_DESCRIPTION, SITE_NAME, SITE_TAGLINE, SITE_URL, absoluteUrl } from "@/lib/seo";
 import "./globals.css";
 
 // Wix Madefor — the platform typeface (body + UI)
@@ -18,21 +21,78 @@ const madeforDisplay = Wix_Madefor_Display({
 });
 
 export const metadata: Metadata = {
+  metadataBase: new URL(SITE_URL),
   title: {
-    default: "Podcast Distribution AI — From topic idea to published podcast in minutes",
-    template: "%s · Podcast Distribution AI",
+    default: `${SITE_NAME} — ${SITE_TAGLINE}`,
+    template: `%s · ${SITE_NAME}`,
   },
-  description:
-    "Podcast Distribution AI is an all-in-one AI platform that writes your script, records realistic multi-voice audio, and designs cover art — turning a topic into a finished episode in minutes.",
-  metadataBase: new URL(process.env.NEXT_PUBLIC_APP_URL || "http://localhost:3000"),
+  description: SITE_DESCRIPTION,
+  applicationName: SITE_NAME,
+  authors: [{ name: SITE_NAME, url: absoluteUrl("/") }],
+  creator: SITE_NAME,
+  publisher: SITE_NAME,
+  category: "technology",
+  keywords: [
+    "AI podcast generator",
+    "podcast script generator",
+    "AI voice over",
+    "text to speech podcast",
+    "podcast cover art generator",
+    "AI podcast production",
+    "content repurposing",
+    "multi-voice AI audio",
+  ],
+  // Every route gets a self-referencing canonical; pages override this with their
+  // own absolute URL via `pageMetadata()` so query strings never fragment a page.
+  alternates: { canonical: absoluteUrl("/") },
   openGraph: {
-    title: "Podcast Distribution AI",
-    description: "Create scripted, narrated, illustrated podcasts with AI — no recording gear required.",
     type: "website",
+    siteName: SITE_NAME,
+    title: `${SITE_NAME} — ${SITE_TAGLINE}`,
+    description: SITE_DESCRIPTION,
+    url: absoluteUrl("/"),
+    locale: "en_US",
+  },
+  twitter: {
+    card: "summary_large_image",
+    title: `${SITE_NAME} — ${SITE_TAGLINE}`,
+    description: SITE_DESCRIPTION,
+  },
+  robots: {
+    index: true,
+    follow: true,
+    googleBot: {
+      index: true,
+      follow: true,
+      "max-image-preview": "large",
+      "max-snippet": -1,
+      "max-video-preview": -1,
+    },
+  },
+  formatDetection: { telephone: false, address: false, email: false },
+  // Search-console ownership tokens; unset values are simply omitted.
+  verification: {
+    google: process.env.NEXT_PUBLIC_GOOGLE_SITE_VERIFICATION,
+    other: process.env.NEXT_PUBLIC_BING_SITE_VERIFICATION
+      ? { "msvalidate.01": process.env.NEXT_PUBLIC_BING_SITE_VERIFICATION }
+      : {},
   },
 };
 
+export const viewport: Viewport = {
+  themeColor: [
+    { media: "(prefers-color-scheme: light)", color: "#ffffff" },
+    { media: "(prefers-color-scheme: dark)", color: "#0d0d0d" },
+  ],
+  colorScheme: "light dark",
+  width: "device-width",
+  initialScale: 1,
+};
+
 export default function RootLayout({ children }: { children: React.ReactNode }) {
+  // Absent config (the default in development) renders nothing at all.
+  const umami = umamiConfig();
+
   return (
     <html lang="en" suppressHydrationWarning>
       <body
@@ -40,6 +100,7 @@ export default function RootLayout({ children }: { children: React.ReactNode })
       >
         {children}
         <Toaster richColors position="top-center" />
+        {umami && <UmamiAnalytics websiteId={umami.websiteId} />}
       </body>
     </html>
   );