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/media-service.ts

@@ -125,7 +125,8 @@ export async function createStandaloneMediaAsset(input: {
   uploadFile: FormDataEntryValue | null;
 }) {
   if (input.uploadFile instanceof File && input.uploadFile.size > 0) {
-    const savedFile = await saveMediaUpload(input.uploadFile, input.kind.toLowerCase());
+    const kind = getKindFromUploadFile(input.uploadFile);
+    const savedFile = await saveMediaUpload(input.uploadFile, kind.toLowerCase());
     const derivedLabel = input.uploadFile.name.replace(/\.[^.]+$/, "").trim();
     const trimmedLabel = input.label.trim() || derivedLabel || "Media asset";
 
@@ -135,7 +136,7 @@ export async function createStandaloneMediaAsset(input: {
 
     return createMediaAsset({
       source: MediaSource.UPLOAD,
-      kind: input.kind,
+      kind,
       url: savedFile.url,
       fileName: savedFile.fileName,
       label: trimmedLabel,