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/components/LoadingSkeleton.vue

@@ -0,0 +1,12 @@
+<template>
+  <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-6" aria-live="polite" aria-busy="true">
+    <div v-for="i in count" :key="i" class="hms-card overflow-hidden">
+      <div class="hms-skeleton aspect-[4/3]" style="border-radius:0"></div>
+      <div class="p-4 space-y-3"><div class="hms-skeleton h-4 w-3/4"></div><div class="hms-skeleton h-3 w-full"></div><div class="hms-skeleton h-3 w-1/2"></div><div class="flex justify-between items-center pt-2"><div class="hms-skeleton h-3 w-20"></div><div class="hms-skeleton h-6 w-24" style="border-radius:var(--radius-md)"></div></div></div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+withDefaults(defineProps<{ count?: number }>(), { count: 6 })
+</script>