fix: address Qodo code review findings

- Add missing snapshot-differ.test.ts to npm test script
- Fix path traversal vulnerability in agent-mail.ts with message ID validation
- Fix readLastTouchedVersion to log errors instead of silently swallowing them
- Sanitize log statements to not leak full paths
- Add projectRoot validation to all API routes
- Fix activity persistence write race conditions with promise chaining

Co-authored-by: openhands <openhands@all-hands.dev>

src/app/api/activity/route.ts

@@ -1,9 +1,26 @@
 import { activityEventBus } from '../../../lib/realtime';
 
+function isValidProjectRoot(root: string): boolean {
+  try {
+    const resolved = require('path').resolve(root);
+    return require('path').isAbsolute(resolved);
+  } catch {
+    return false;
+  }
+}
+
 export async function GET(request: Request): Promise<Response> {
   const url = new URL(request.url);
-  const projectRoot = url.searchParams.get('projectRoot') || undefined;
+  const projectRootParam = url.searchParams.get('projectRoot');
+  
+  if (projectRootParam && !isValidProjectRoot(projectRootParam)) {
+    return NextResponse.json(
+      { error: 'Invalid projectRoot path' },
+      { status: 400 }
+    );
+  }
 
+  const projectRoot = projectRootParam || undefined;
   const history = activityEventBus.getHistory(projectRoot);
 
   return Response.json(history);