Add WebSocket Connection Testing Scripts

- Introduced two new test scripts: `test-relay-connection.js` and `test-websocket-close.js` to verify WebSocket connection stability and closure behavior.
- `test-relay-connection.js` tests multiple connections, monitors their open/close events, and analyzes premature closures.
- `test-websocket-close.js` focuses on connection closure issues with concurrent connections and logs results for connected, closed, and error states.
- Both scripts utilize the NostrWebSocket from the @nostr-dev-kit/ndk package for testing purposes.

test-websocket-close.js

@@ -0,0 +1,57 @@
+import { NostrWebSocket } from '@nostr-dev-kit/ndk';
+
+const RELAY = process.env.RELAY || 'ws://localhost:8080';
+
+async function testConnectionClosure() {
+    console.log('Testing websocket connection closure issues...');
+    console.log('Connecting to:', RELAY);
+
+    // Create multiple connections to test concurrency
+    const connections = [];
+    const results = { connected: 0, closed: 0, errors: 0 };
+
+    for (let i = 0; i < 5; i++) {
+        const ws = new NostrWebSocket(RELAY);
+        
+        ws.addEventListener('open', () => {
+            console.log(`Connection ${i} opened`);
+            results.connected++;
+        });
+
+        ws.addEventListener('close', (event) => {
+            console.log(`Connection ${i} closed:`, event.code, event.reason);
+            results.closed++;
+        });
+
+        ws.addEventListener('error', (error) => {
+            console.error(`Connection ${i} error:`, error);
+            results.errors++;
+        });
+
+        connections.push(ws);
+    }
+
+    // Wait a bit then send REQs
+    await new Promise(resolve => setTimeout(resolve, 1000));
+
+    // Send some REQ messages
+    for (const ws of connections) {
+        ws.send(JSON.stringify(['REQ', 'test-sub', { kinds: [1] }]));
+    }
+
+    // Wait and observe behavior
+    await new Promise(resolve => setTimeout(resolve, 5000));
+
+    console.log('\nTest Results:');
+    console.log(`- Connected: ${results.connected}`);
+    console.log(`- Closed prematurely: ${results.closed}`);
+    console.log(`- Errors: ${results.errors}`);
+
+    // Close all connections
+    for (const ws of connections) {
+        ws.close();
+    }
+}
+
+testConnectionClosure().catch(console.error);
+