fix(inspector): bring back the actor inspector (#1174)

Closes FRONT-763

### TL;DR

Added actor inspector tests to the driver test suite to ensure inspector functionality works correctly across different drivers.

### What changed?

- Added `runActorInspectorTests` to the driver test suite
- Created a new test file `actor-inspector.ts` with comprehensive tests for both manager and actor inspectors
- Enabled studio in the test runtime configuration to support inspector tests
- Fixed a bug in the file system driver's `getActorsIterator` to check if the state directory exists
- Fixed a validation issue in the manager inspector router to properly handle invalid limit parameters
- Fixed URL path handling in the universal actor proxy to correctly handle leading slashes

### How to test?

Run the driver test suite with:

```
pnpm test
```

The new tests verify:

- Manager inspector functionality (ping, actor listing, actor creation, etc.)
- Actor inspector functionality (state management, connections, events, RPCs)
- Error handling for both inspectors

### Why make this change?

The inspector functionality is a critical part of the developer experience, allowing users to debug and inspect actors. These tests ensure that inspector functionality works consistently across all drivers, improving reliability and preventing regressions.

Author: jog1t

packages/core/src/driver-test-suite/mod.ts

@@ -17,6 +17,7 @@ import { runActorDriverTests } from "./tests/actor-driver";
 import { runActorErrorHandlingTests } from "./tests/actor-error-handling";
 import { runActorHandleTests } from "./tests/actor-handle";
 import { runActorInlineClientTests } from "./tests/actor-inline-client";
+import { runActorInspectorTests } from "./tests/actor-inspector";
 import { runActorMetadataTests } from "./tests/actor-metadata";
 import { runActorVarsTests } from "./tests/actor-vars";
 import { runManagerDriverTests } from "./tests/manager-driver";
@@ -119,6 +120,8 @@ export function runDriverTests(
 			runRawHttpDirectRegistryTests(driverTestConfig);
 
 			runRawWebSocketDirectRegistryTests(driverTestConfig);
+
+			runActorInspectorTests(driverTestConfig);
 		});
 	}
 }
@@ -154,6 +157,10 @@ export async function createTestRuntime(
 	const config: RunConfig = RunConfigSchema.parse({
 		driver,
 		getUpgradeWebSocket: () => upgradeWebSocket!,
+		studio: {
+			enabled: true,
+			token: () => "token",
+		},
 	});
 
 	// Create router