dsh-web-guard: Adds password protection to the DSH Web UI and fixes the /api 403 issue caused by reverse proxying.

dsh-web-guard (maintained by lvxianchao, MIT, npm 3.0.0) adds a password gate to the DeepSeek Harness Web UI: providing an access password, revocable sessions, a native settings page, and TLS. It also fixes the 403 error on `/api` resulting from NPM or Caddy reverse proxying. With zero runtime dependencies, it requires DSH >= 0.2.2-rc.1 < 0.3.0 and Node >= 22.19. The article provides three installation commands for `dsh plugin --profile web add`, the `cordis.patch.yml` configuration, and details on TLS and reverse proxy topology. It is crucial to emphasize that this is the sole entry point; do not uninstall or disable it, and a recovery path bypassing the gate must be reserved.