Add plugin telemetry bridge capability

Expose telemetry.track through the plugin SDK and server host bridge, forward plugin-prefixed events into the shared telemetry client, and demonstrate the capability in the kitchen sink example.\n\nCo-Authored-By: Paperclip <noreply@paperclip.ing>

packages/shared/src/constants.ts

@@ -448,6 +448,7 @@ export const PLUGIN_CAPABILITIES = [
   "agent.sessions.close",
   "activity.log.write",
   "metrics.write",
+  "telemetry.track",
   // Plugin State
   "plugin.state.read",
   "plugin.state.write",

packages/shared/src/telemetry/types.ts

@@ -33,4 +33,5 @@ export type TelemetryEventName =
   | "company.imported"
   | "agent.first_heartbeat"
   | "agent.task_completed"
-  | "error.handler_crash";
+  | "error.handler_crash"
+  | `plugin.${string}`;