🤖 fix: make temp directory cleanup non-blocking for faster stream interruption

When interrupting a stream (especially on SSH), the UI was delayed by 500ms-2s
waiting for the temp directory cleanup to complete. The cleanup involved an
SSH 'rm -rf' command that blocked the processingPromise resolution, which
delayed the stream-abort event emission.

This change makes temp directory cleanup fire-and-forget, so the stream-abort
event is emitted immediately after the stream breaks out of the processing loop,
providing instant UI feedback.

The cleanup is still guaranteed to happen (via void promise), but it no longer
blocks the critical path for UI responsiveness.

_Generated with `cmux`_

Author: ammar-agent

src/services/streamManager.ts

@@ -978,19 +978,22 @@ export class StreamManager extends EventEmitter {
         streamInfo.partialWriteTimer = undefined;
       }
 
-      // Clean up stream temp directory using runtime
+      // Clean up stream temp directory using runtime (fire-and-forget)
+      // Don't block stream completion waiting for directory deletion
+      // This is especially important for SSH where rm -rf can take 500ms-2s
       if (streamInfo.runtimeTempDir) {
-        try {
-          const result = await streamInfo.runtime.exec(`rm -rf "${streamInfo.runtimeTempDir}"`, {
+        void streamInfo.runtime
+          .exec(`rm -rf "${streamInfo.runtimeTempDir}"`, {
             cwd: "~",
             timeout: 10,
+          })
+          .then(async (result) => {
+            await result.exitCode;
+            log.debug(`Cleaned up temp dir: ${streamInfo.runtimeTempDir}`);
+          })
+          .catch((error) => {
+            log.error(`Failed to cleanup temp dir ${streamInfo.runtimeTempDir}:`, error);
           });
-          await result.exitCode; // Wait for completion
-          log.debug(`Cleaned up temp dir: ${streamInfo.runtimeTempDir}`);
-        } catch (error) {
-          log.error(`Failed to cleanup temp dir ${streamInfo.runtimeTempDir}:`, error);
-          // Don't throw - cleanup is best-effort
-        }
       }
 
       this.workspaceStreams.delete(workspaceId);