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/(marketing)/features/page.tsx

@@ -1,4 +1,5 @@
 import type { Metadata } from "next";
+import Image from "next/image";
 import Link from "next/link";
 import {
   ArrowRight,
@@ -33,12 +34,19 @@ import {
 import { Button } from "@/components/ui/button";
 import { Card, CardContent } from "@/components/ui/card";
 import { Badge } from "@/components/ui/badge";
+import { JsonLd } from "@/components/seo/json-ld";
+import { breadcrumbSchema, graph, softwareApplicationSchema, webPageSchema } from "@/lib/schema";
+import { pageMetadata } from "@/lib/seo";
 
-export const metadata: Metadata = {
+/** Shared by the page metadata and this page's structured data. */
+const DESCRIPTION =
+  "Everything Podcast Distribution AI does — AI scriptwriting, realistic multi-voice audio, cover art, repurposing, a season generator, 13+ languages, team white-label, an API, and more.";
+
+export const metadata: Metadata = pageMetadata({
   title: "Features",
-  description:
-    "Everything Podcast Distribution AI does — AI scriptwriting, realistic multi-voice audio, cover art, repurposing, a season generator, 13+ languages, team white-label, an API, and more.",
-};
+  description: DESCRIPTION,
+  path: "/features",
+});
 
 const HERO_IMG =
   "https://images.unsplash.com/photo-1590602847861-f357a9332bbc?auto=format&fit=crop&w=1600&q=80";
@@ -50,6 +58,18 @@ const TEAM_IMG =
 export default function FeaturesPage() {
   return (
     <>
+      <JsonLd
+        data={graph(
+          webPageSchema({
+            path: "/features",
+            name: "Features",
+            description: DESCRIPTION,
+          }),
+          breadcrumbSchema([{ name: "Features", path: "/features" }]),
+          softwareApplicationSchema()
+        )}
+      />
+
       {/* 1 — Hero */}
       <section className="relative overflow-hidden bg-hero-wash">
         <div className="container grid items-center gap-12 py-20 md:grid-cols-2 md:py-28">
@@ -79,13 +99,16 @@ export default function FeaturesPage() {
           </div>
           <div className="relative">
             <div className="overflow-hidden rounded-3xl border border-border shadow-xl">
-              {/* eslint-disable-next-line @next/next/no-img-element */}
-              <img
+              {/* Above the fold — the LCP element on this page, so it is
+                  fetched eagerly at high priority rather than lazily. */}
+              <Image
                 src={HERO_IMG}
                 alt="Studio condenser microphone"
                 className="h-full w-full object-cover"
                 width={1600}
                 height={1067}
+                sizes="(max-width: 768px) 100vw, 50vw"
+                priority
               />
             </div>
             <div className="absolute -bottom-5 -left-5 hidden rounded-2xl border border-border bg-card p-4 shadow-lg sm:block">
@@ -534,8 +557,16 @@ function FeatureBand({
         <div className={reverse ? "md:order-1" : ""}>
           {image ? (
             <div className="overflow-hidden rounded-3xl border border-border shadow-xl">
-              {/* eslint-disable-next-line @next/next/no-img-element */}
-              <img src={image} alt={imageAlt ?? ""} className="h-full w-full object-cover" width={1400} height={933} />
+              {/* Below the fold — lazy by default, and served in a modern
+                  format at the size the column actually renders at. */}
+              <Image
+                src={image}
+                alt={imageAlt ?? ""}
+                className="h-full w-full object-cover"
+                width={1400}
+                height={933}
+                sizes="(max-width: 768px) 100vw, 50vw"
+              />
             </div>
           ) : (
             visual