feat: add MCP server with resources, tools, auth, and Traefik routing

- Add backend/app/mcp_server.py with FastMCP server (hms-cms)
- Resources: design-rules, page-structure, sync-status
- Tools: trigger_sync, get_sync_log, set_rentman_token, read_file,
  write_file, create_page, deploy, git_commit, git_status
- Bearer token auth via MCP_AUTH_TOKEN env var
- Mount MCP at /mcp with streamable HTTP transport
- Integrate session manager in FastAPI lifespan
- Add Traefik labels for external /mcp route on hms.media-on.de
- Add git, docker.io, curl to backend Dockerfile
- Mount repo root + docker socket in backend container
- Add mcp>=1.0.0 to requirements.txt

frontend-nuxt-old/layouts/default.vue

@@ -0,0 +1,14 @@
+<template>
+  <div class="min-h-screen flex flex-col">
+    <a href="#main-content" class="skip-link">Zum Hauptinhalt springen</a>
+    <AppHeader />
+    <main id="main-content" class="flex-1" role="main">
+      <slot />
+    </main>
+    <AppFooter />
+  </div>
+</template>
+
+<script setup lang="ts">
+// Default layout – Header + Main + Footer
+</script>