test: Migrate test suite to Bun's native testing framework

- Update test files to use Bun's native test and mocking utilities
- Replace Jest-specific imports and mocking techniques with Bun equivalents
- Refactor test setup to use Bun's mock module and testing conventions
- Add new `test/setup.ts` for global test configuration and mocks
- Improve test reliability and simplify mocking approach
- Update TypeScript configuration to support Bun testing ecosystem

test/setup.ts

@@ -0,0 +1,66 @@
+import { afterEach, mock, expect } from "bun:test";
+
+// Setup global mocks
+global.fetch = mock(() => Promise.resolve(new Response()));
+
+// Mock WebSocket
+class MockWebSocket {
+    static CONNECTING = 0;
+    static OPEN = 1;
+    static CLOSING = 2;
+    static CLOSED = 3;
+
+    url: string;
+    readyState: number = MockWebSocket.CLOSED;
+    onopen: ((event: any) => void) | null = null;
+    onclose: ((event: any) => void) | null = null;
+    onmessage: ((event: any) => void) | null = null;
+    onerror: ((event: any) => void) | null = null;
+
+    constructor(url: string) {
+        this.url = url;
+        setTimeout(() => {
+            this.readyState = MockWebSocket.OPEN;
+            this.onopen?.({ type: 'open' });
+        }, 0);
+    }
+
+    send = mock((data: string) => {
+        if (this.readyState !== MockWebSocket.OPEN) {
+            throw new Error('WebSocket is not open');
+        }
+    });
+
+    close = mock(() => {
+        this.readyState = MockWebSocket.CLOSED;
+        this.onclose?.({ type: 'close', code: 1000, reason: '', wasClean: true });
+    });
+}
+
+// Add WebSocket to global
+(global as any).WebSocket = MockWebSocket;
+
+// Reset all mocks after each test
+afterEach(() => {
+    mock.restore();
+});
+
+// Add custom matchers
+expect.extend({
+    toBeValidResponse(received: Response) {
+        const pass = received instanceof Response && received.ok;
+        return {
+            message: () =>
+                `expected ${received instanceof Response ? 'Response' : typeof received} to${pass ? ' not' : ''} be a valid Response`,
+            pass
+        };
+    },
+    toBeValidWebSocket(received: any) {
+        const pass = received instanceof MockWebSocket;
+        return {
+            message: () =>
+                `expected ${received instanceof MockWebSocket ? 'MockWebSocket' : typeof received} to${pass ? ' not' : ''} be a valid WebSocket`,
+            pass
+        };
+    }
+});