Completes D3 of the dashboard plugin plan. The manifest declares
the plugin at /relay (after:skills), icon "Activity" (on upstream
whitelist), entry dist/index.js, backend plugin_api.py. Commits
the plan file under docs/plans/ alongside existing feature plans.
With this ref in place, a hermes-agent dashboard scanning
~/.hermes/plugins/hermes-relay/dashboard/ (via the existing symlink
to plugin/) will discover the plugin on startup or via
POST /api/dashboard/plugins/rescan.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
