fix(gemini-adapter): handle stdout close events

Addressed the Gemini CLI streaming regression where readline could emit a close event without any lines, leaving iterators waiting forever. Added a close handler that emits cancelled/error metadata for aborted runs and always pushes the DONE sentinel before cleanup detaches the listener, and updated the spawn cleanup helper to remove the new handler safely. Verified via npm run test --workspace examples.

Author: OhadAssulin

packages/gemini-adapter/src/index.ts

@@ -247,6 +247,22 @@ export class GeminiAdapter implements HeadlessCoder {
       }
     };
     rl.on('line', handleLine);
+    const handleClose = () => {
+      if (finished) return;
+      finished = true;
+      if (active.aborted) {
+        const reason = active.abortReason ?? 'Interrupted';
+        push({
+          type: 'cancelled',
+          provider: CODER_NAME,
+          ts: now(),
+          originalItem: { reason },
+        });
+        push(interruptedErrorEvent(reason));
+      }
+      push(DONE);
+    };
+    rl.once('close', handleClose);
 
     const onExit = (code: number | null) => {
       if (finished) return;
@@ -287,7 +303,7 @@ export class GeminiAdapter implements HeadlessCoder {
             yield entry;
           }
         } finally {
-          cleanup(handleLine, rl);
+          cleanup(handleLine, rl, handleClose);
           if (!finished && !active.aborted) {
             this.abortChild(state, 'Stream closed');
           }
@@ -363,11 +379,18 @@ export class GeminiAdapter implements HeadlessCoder {
     return {
       child,
       active,
-      cleanup: (lineHandler?: (line: string) => void, rl?: readline.Interface) => {
+      cleanup: (
+        lineHandler?: (line: string) => void,
+        rl?: readline.Interface,
+        closeHandler?: () => void,
+      ) => {
         stopExternal();
         this.clearKillTimers(active);
         if (lineHandler && rl) {
           rl.off('line', lineHandler);
+          if (closeHandler) {
+            rl.off('close', closeHandler);
+          }
           rl.close();
         }
         destroyChildStreams(child);