hermes-webui: add Hermex server as loopback compose service on Dankclaw

- compose: hermes-webui runs bootstrap.py --foreground in the agent image,
  shares /home/dank/hermes-data (same uid mapping as the gateway), publishes
  127.0.0.1:8787 only; password from host .env
- planner/remote deployer: hermes-webui is an isolated Dankclaw service
- tests: deployment integrity seam (loopback, auth, volume, healthcheck,
  planner narrowing, deployer dispatch)
- docs: Hermes-WebUI page with the iOS SSH-tunnel access pattern

docs/index.md

@@ -62,6 +62,7 @@ covers both workloads).
 - [[OpenWebUI]] — chat UI for local LLMs
 - [[Hermes]] — the Nous Research agent
 - [[Hermes-Dashboard]] — the Hermes web management UI (config, keys, sessions)
+- [[Hermes-WebUI]] — the Hermex server (loopback API for the iPhone app, SSH-tunneled)
 - [[Gitea]] — Git hosting (migrated)
 - [[Postgres]] — Gitea database backend