fix(async): clear all timers to prevent coverage hang

Fixed async resource cleanup preventing vitest coverage from completing:

**MCP Aggregator** (aggregator.ts):
- Track reconnect timers in MCPConnection interface
- Clear reconnect timers in shutdown method
- Prevents setTimeout from keeping process alive

**QuickJS Sandbox** (quickjs-runtime.ts):
- Track recursive check timer in waitForWorker
- Clear timeout in executeWithTimeout error path
- Prevents recursive setTimeout loop

Root cause: Untracked setTimeout/setInterval calls kept Node event
loop active after tests completed, preventing clean exit.

Impact: Coverage runs should now complete successfully instead of
hanging indefinitely after tests finish.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: danieliser

src/mcp/aggregator.ts

@@ -18,6 +18,7 @@ export interface MCPConnection {
   lastSeen: Date;
   tools: Map<string, ToolInfo>;
   retryCount: number;
+  reconnectTimer?: NodeJS.Timeout;
 }
 
 export class MCPAggregator extends EventEmitter {
@@ -396,11 +397,17 @@ export class MCPAggregator extends EventEmitter {
 
     console.log(`⏳ Scheduling reconnect for ${serverName} in ${delay}ms (attempt ${connection.retryCount}/${this.maxRetries})`);
 
-    setTimeout(async () => {
+    // Clear any existing reconnect timer
+    if (connection.reconnectTimer) {
+      clearTimeout(connection.reconnectTimer);
+    }
+
+    connection.reconnectTimer = setTimeout(async () => {
       if (connection.status === 'error') {
         console.log(`🔄 Retrying connection to ${serverName}...`);
         await this.connectServer(serverName, connection.config);
       }
+      connection.reconnectTimer = undefined;
     }, delay);
   }
 
@@ -439,6 +446,14 @@ export class MCPAggregator extends EventEmitter {
       this.healthCheckInterval = null;
     }
 
+    // Clear all reconnect timers
+    for (const connection of this.connections.values()) {
+      if (connection.reconnectTimer) {
+        clearTimeout(connection.reconnectTimer);
+        connection.reconnectTimer = undefined;
+      }
+    }
+
     // Close all connections
     const shutdownPromises = Array.from(this.connections.values()).map(
       async (connection) => {

src/sandbox/quickjs-runtime.ts

@@ -144,16 +144,19 @@ export class QuickJSSandbox {
 
   private async waitForWorker(): Promise<SandboxWorker> {
     return new Promise((resolve, reject) => {
+      let checkTimer: NodeJS.Timeout | null = null;
       const timeout = setTimeout(() => {
+        if (checkTimer) clearTimeout(checkTimer);
         reject(new Error('Timeout waiting for available worker'));
       }, 5000);
 
       const checkForWorker = () => {
         if (this.workerQueue.length > 0) {
+          if (checkTimer) clearTimeout(checkTimer);
           clearTimeout(timeout);
           resolve(this.acquireWorker());
         } else {
-          setTimeout(checkForWorker, 10);
+          checkTimer = setTimeout(checkForWorker, 10);
         }
       };
 
@@ -225,6 +228,7 @@ export class QuickJSSandbox {
         if (result.error) {
           const error = context.getString(result.error);
           result.error.dispose();
+          clearTimeout(timeoutId);
           reject(new Error(error));
         } else if ('value' in result) {
           const value = result.value;