chore: update .gitignore and improve cleanup handling in scripts

- Added .claude/hans/ to .gitignore to prevent tracking of specific directory.
- Updated cleanup calls in dev.mjs and start.mjs to use await for proper asynchronous handling.
- Enhanced error handling during cleanup in case of failures.
- Improved server failure handling in startServerAndWait function to ensure proper termination of failed processes.

dev.mjs

@@ -117,7 +117,7 @@ async function main() {
       });
 
       if (!processes.server) {
-        cleanup();
+        await cleanup();
         process.exit(1);
       }
 
@@ -175,9 +175,13 @@ async function main() {
 }
 
 // Run main function
-main().catch((err) => {
+main().catch(async (err) => {
   console.error(err);
   const cleanup = createCleanupHandler(processes);
-  cleanup();
+  try {
+    await cleanup();
+  } catch (cleanupErr) {
+    console.error('Cleanup error:', cleanupErr);
+  }
   process.exit(1);
 });