Extend the local plugin system's host<->plugin contract with generic,
capability-neutral facilities, so transport plugins can be built on top
without embedding plugin-specific logic in the host.
Host services (plugin dials a broker-provided HostService gRPC):
- per-plugin namespaced KV store (key/value size and TTL bounded)
- account directory: ListAccounts + ResolveOutboundIdentity, restricted to
the accounts a plugin's declared capability already covers
- InitHostServices lifecycle hook; plugins that don't implement it run
unchanged and are simply offered no host services
Read-only runtime status channel:
- HealthResponse gains an opaque, plugin-defined status_json produced
passively (no config apply, no upstream call, no side effects)
- GET /admin/plugins/:id/status (ungated) and the plugin.status UI-bridge
verb map to Health, so a status UI can poll live state without a step-up
prompt or a "test" side effect
- config.test no longer force-shows a host success toast; the plugin UI owns
result presentation, so plugins that read status do not spam toasts
Document the UI-bridge verb taxonomy (read vs mutate/test gating) and the
status contract under pkg/pluginapi.