feat(drivers/engine): pass inspector to metadata (#1184)

### TL;DR

Updated the engine-runner dependency to version 4b0f765 and enhanced actor metadata handling.

### What changed?

- Updated `@rivetkit/engine-runner` from version f8860f3 to 4b0f765
- Added inspector token to actor metadata for improved debugging capabilities
- Modified the prepopulation of actor names to use an object structure with metadata
- Added automatic generation of a random studio token if one doesn't exist
- Removed unused imports (`noopNext`, `WSContext`, `InternalError`)

### How to test?

1. Run the application with the updated engine-runner
2. Verify that actors are properly initialized with metadata
3. Check that the inspector token is correctly passed to the engine runner
4. Confirm that reconnection logic works as expected

### Why make this change?

This change enhances the actor system by providing better metadata support, which improves debugging capabilities through the inspector token. The updated engine-runner version includes improvements that require these structural changes to the actor initialization process. The automatic token generation ensures that the system always has a valid token for studio operations.

Author: jog1t

packages/core/package.json

@@ -167,7 +167,7 @@
     "on-change": "^5.0.1",
     "p-retry": "^6.2.1",
     "zod": "^3.25.76",
-    "@rivetkit/engine-runner": "https://pkg.pr.new/rivet-gg/engine/@rivetkit/engine-runner@f8860f3"
+    "@rivetkit/engine-runner": "https://pkg.pr.new/rivet-gg/engine/@rivetkit/engine-runner@4b0f765"
   },
   "devDependencies": {
     "@hono/node-server": "^1.18.2",

packages/core/src/drivers/engine/actor-driver.ts

@@ -31,7 +31,6 @@ import {
 	handleRawWebSocketHandler,
 	handleWebSocketConnect,
 	lookupInRegistry,
-	noopNext,
 	PATH_CONNECT_WEBSOCKET,
 	PATH_RAW_WEBSOCKET_PREFIX,
 } from "@/mod";
@@ -85,7 +84,15 @@ export class EngineActorDriver implements ActorDriver {
 			totalSlots: config.totalSlots,
 			runnerName: config.runnerName,
 			runnerKey: config.runnerKey,
-			prepopulateActorNames: Object.keys(this.#registryConfig.use),
+			metadata: {
+				inspectorToken: this.#runConfig.studio.token(),
+			},
+			prepopulateActorNames: Object.fromEntries(
+				Object.keys(this.#registryConfig.use).map((name) => [
+					name,
+					{ metadata: {} },
+				]),
+			),
 			onConnected: () => {
 				if (hasDisconnected) {
 					logger().info("runner reconnected", {

packages/core/src/drivers/engine/manager-driver.ts

@@ -1,14 +1,14 @@
 import * as cbor from "cbor-x";
 import type { Context as HonoContext } from "hono";
-import type { WSContext } from "hono/ws";
 import invariant from "invariant";
-import { ActorAlreadyExists, InternalError } from "@/actor/errors";
+import { ActorAlreadyExists } from "@/actor/errors";
 import {
 	HEADER_AUTH_DATA,
 	HEADER_CONN_PARAMS,
 	HEADER_ENCODING,
 	HEADER_EXPOSE_INTERNAL_ERROR,
 } from "@/actor/router-endpoints";
+import { generateRandomString } from "@/actor/utils";
 import { importWebSocket } from "@/common/websocket";
 import type {
 	ActorOutput,
@@ -40,6 +40,10 @@ export class EngineManagerDriver implements ManagerDriver {
 	constructor(config: Config, runConfig: RunConfig) {
 		this.#config = config;
 		this.#runConfig = runConfig;
+		if (!this.#runConfig.studio.token()) {
+			const token = generateRandomString();
+			this.#runConfig.studio.token = () => token;
+		}
 		this.#importWebSocketPromise = importWebSocket();
 	}