fix: improve abort handling in spawnJSONLProcess

- Added immediate invocation of abort handler if the abort signal is already triggered, ensuring proper cleanup.
- Updated test to use setImmediate for aborting, allowing the generator to start processing before the abort is called, enhancing reliability.

libs/platform/src/subprocess.ts

@@ -97,7 +97,12 @@ export async function* spawnJSONLProcess(options: SubprocessOptions): AsyncGener
       }
       childProcess.kill('SIGTERM');
     };
-    abortController.signal.addEventListener('abort', abortHandler);
+    // Check if already aborted, if so call handler immediately
+    if (abortController.signal.aborted) {
+      abortHandler();
+    } else {
+      abortController.signal.addEventListener('abort', abortHandler);
+    }
   }
 
   // Helper to clean up abort listener

libs/platform/tests/subprocess.test.ts

@@ -245,7 +245,7 @@ describe('subprocess.ts', () => {
       const mockProcess = createMockProcess({
         stdoutLines: ['{"type":"start"}'],
         exitCode: 0,
-        delayMs: 100, // Delay to allow abort
+        delayMs: 200, // Delay to allow abort
       });
 
       vi.mocked(cp.spawn).mockReturnValue(mockProcess);
@@ -258,8 +258,11 @@ describe('subprocess.ts', () => {
       // Start consuming the generator
       const promise = collectAsyncGenerator(generator);
 
-      // Abort after a short delay
-      setTimeout(() => abortController.abort(), 20);
+      // Abort after a short delay to ensure generator has started
+      // Use setImmediate to ensure the generator has started processing
+      setImmediate(() => {
+        abortController.abort();
+      });
 
       await promise;