Add Clay agent interface, fix registry UI routing, and misc improvements

- Deploy Clay (claude Code web UI) at agent.ladkau.de behind basic auth;
  Traefik proxies to clay's HTTPS port 2633 with insecureSkipVerify
- Document MCP server persistence: binaries need to be baked into the
  Dockerfile, config in /opt/clay/data survives rebuilds
- Document scheduled agent workflows via Gitea Actions on.schedule with
  email reporting via Gmail SMTP
- Fix registry UI: split /v2/ (registry) and / (UI) into separate Traefik
  routers; add registry_internal network
- Add weekly registry GC cron job (/usr/local/bin/registry-gc)
- Remove rate-limit middleware from Gitea router (act_runner polling
  exceeded 60 req/min limit)
- Set Traefik websecure readTimeout: 0 to fix large layer upload 499s

ansible/roles/clay/templates/docker-compose.yml.j2

@@ -0,0 +1,35 @@
+# Managed by Ansible — do not edit manually
+services:
+  clay:
+    image: clay:local
+    build:
+      context: {{ clay_data_dir }}
+      dockerfile: Dockerfile
+    container_name: clay
+    restart: unless-stopped
+    tty: true
+    environment:
+      - ANTHROPIC_API_KEY={{ anthropic_api_key }}
+    volumes:
+      - {{ clay_data_dir }}/data:/root/.clay
+      - {{ clay_data_dir }}/workspace:/workspace
+    command: ["clay-server", "--yes", "-p", "2633"]
+    networks:
+      - traefik_public
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.clay.rule=Host(`{{ domain_clay }}`)"
+      - "traefik.http.routers.clay.entrypoints=websecure"
+      - "traefik.http.routers.clay.tls.certresolver=letsencrypt"
+      - "traefik.http.services.clay.loadbalancer.server.scheme=https"
+      - "traefik.http.services.clay.loadbalancer.server.port=2633"
+      - "traefik.http.routers.clay.middlewares=clay-auth"
+{% set ns = namespace(entries=[]) %}
+{% for user in clay_users %}
+{% set ns.entries = ns.entries + [user.username + ':' + (user.password | password_hash('bcrypt', (user.username | hash('md5'))[:22]) | replace('$', '$$'))] %}
+{% endfor %}
+      - "traefik.http.middlewares.clay-auth.basicauth.users={{ ns.entries | join(',') }}"
+
+networks:
+  traefik_public:
+    external: true