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/files/Dockerfile

@@ -0,0 +1,20 @@
+FROM node:20-alpine
+
+# Claude Code needs git and bash to operate on repositories
+RUN apk add --no-cache git bash curl
+
+# Install Claude Code CLI
+RUN npm install -g @anthropic-ai/claude-code
+
+# Install clay web server
+RUN npm install -g clay-server
+
+# MCP servers and skills — add packages here to survive container rebuilds
+# RUN npm install -g @clay-ai/clay-ralph
+# RUN npm install -g @modelcontextprotocol/server-filesystem
+
+RUN mkdir -p /workspace /root/.clay
+
+WORKDIR /workspace
+
+EXPOSE 2633