ADDED - Admin SEO page, robots/sitemap hardening and media/maintenance security fixes

SEO
- New Settings > SEO admin page (seo_settings in app_config): indexing switch,
  Google/Bing verification, X handle, JSON-LD identity (Person/Organization,
  sameAs), per-locale keywords, readiness checklist and open links for
  sitemap.xml / robots.txt / manifest.
- robots.txt is now dynamic: disallows admin, api, success and coming-soon
  paths; blocks everything while indexing is off or maintenance is on.
- sitemap.xml carries hreflang alternates per URL, lists only categories with
  published projects, and is empty while hidden.
- Metadata: robots + verification meta, og:locale in de_DE/en_US/ar_AR form,
  alternateLocale, twitter site/creator, project cover as OG image with
  article type, noindex on /success and /coming-soon.
- JSON-LD: WebSite + publisher graph on all public pages, CreativeWork per
  project (view-mode independent).

Security
- Maintenance bypass now requires a correctly signed admin cookie; the
  middleware previously only checked the cookie existed. Token helpers moved
  to lib/admin-session-token.ts (shared by proxy.ts and lib/admin-auth.ts).
- Media uploads: magic-byte validation against the declared type, SVG
  sanitization (script/handlers/foreignObject/javascript: rejected), upload
  folder sanitized, kind inferred from the real file.
- Media route: fixed prefix-based path check that accepted sibling
  directories, unknown extensions return 404, nosniff header, CSP sandbox on
  SVG, gif content type added.
- External media URLs: protocol-relative (//host) URLs rejected.

Portfolio
- Project and category slugs share /portfolio/[slug]; saving now rejects a
  slug already used on the other side instead of silently shadowing it.

Tooling/docs
- Lint: ignore scripts/legacy-prisma-seed.cjs, drop unused import.
- New docs/SEO.md; FEATURES, ARCHITECTURE (Drizzle instead of Prisma), admin
  spec and CLAUDE.md updated.
- Tests for all of the above (unit + integration); suite green.

lib/admin-navigation.ts

@@ -7,6 +7,7 @@ import {
   Mail,
   Palette,
   PlusSquare,
+  Search,
   ShieldAlert,
   SwatchBook,
   Tags,
@@ -24,6 +25,7 @@ type AdminNavigationCopy = {
   siteSettings: string;
   brandSettings?: string;
   localizationSettings?: string;
+  seoSettings?: string;
   marquee?: string;
   smtp?: string;
 };
@@ -41,7 +43,7 @@ export function getAdminNavigation(
   copy: AdminNavigationCopy,
   active: "overview" | "maintenance" | "ui-kit" | "portfolio" | "media" | "site-settings" | "smtp" | "marquee",
   portfolioChild?: "overview" | "projects" | "new-project" | "categories",
-  siteSettingsChild?: "brand" | "localization",
+  siteSettingsChild?: "brand" | "localization" | "seo",
 ): AdminNavItem[] {
   return [
     {
@@ -87,6 +89,12 @@ export function getAdminNavigation(
           icon: Languages,
           active: siteSettingsChild === "localization",
         },
+        {
+          label: copy.seoSettings ?? "SEO",
+          href: getAdminAppPath("/site-settings/seo"),
+          icon: Search,
+          active: siteSettingsChild === "seo",
+        },
       ],
     },
     {