Prevent infinite stream iteration when func host task terminates

[Copilot]

The async iteration over task.stream in the onFuncTaskStarted event handler could hang indefinitely when the task ends, as the stream might not close properly.

Changes:

• Added AbortController to IRunningFuncTask to signal stream termination
• Abort the stream iteration in onDidEndTask handler before removing task from map
• Check abort signal in iteration loop to break cleanly
• Wrapped iteration in try-catch to handle stream errors without crashing the extension

// In onDidEndTask handler
const task = runningFuncTaskMap.get(scope, cwd);
if (task?.streamAbortController) {
    task.streamAbortController.abort();
}

// In stream iteration loop
for await (const chunk of task.stream ?? []) {
    if (task.streamAbortController?.signal.aborted) {
        break;
    }
    // ... process chunk
}

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