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/plugins/sdk/src/host-client-factory.ts

@@ -135,6 +135,11 @@ export interface HostServices {
     write(params: WorkerToHostMethods["metrics.write"][0]): Promise<void>;
   };
 
+  /** Provides `telemetry.track`. */
+  telemetry: {
+    track(params: WorkerToHostMethods["telemetry.track"][0]): Promise<void>;
+  };
+
   /** Provides `log`. */
   logger: {
     log(params: WorkerToHostMethods["log"][0]): Promise<void>;
@@ -284,6 +289,9 @@ const METHOD_CAPABILITY_MAP: Record<WorkerToHostMethodName, PluginCapability | n
   // Metrics
   "metrics.write": "metrics.write",
 
+  // Telemetry
+  "telemetry.track": "telemetry.track",
+
   // Logger — always allowed
   "log": null,
 
@@ -447,6 +455,11 @@ export function createHostClientHandlers(
       return services.metrics.write(params);
     }),
 
+    // Telemetry
+    "telemetry.track": gated("telemetry.track", async (params) => {
+      return services.telemetry.track(params);
+    }),
+
     // Logger
     "log": gated("log", async (params) => {
       return services.logger.log(params);