⚡ Bolt: [parallelize cache directory cleanup]

[acebytes]

💡 What: Converted the sequential removeContents method in CacheCleaner to an async nonisolated method that deletes directory contents concurrently using a withThrowingTaskGroup (sliding window capped at 8 workers).
🎯 Why: Cache directories (like Xcode DerivedData) can contain hundreds of subdirectories. Deleting them sequentially is slow and creates an I/O bottleneck. Parallelizing FileManager.removeItem speeds up the permanent deletion process significantly.
📊 Impact: Reduces cleanup time for large cache categories (like npm, CocoaPods, Xcode DerivedData) by running deletions concurrently.
🔬 Measurement: Verify by clearing a large Xcode DerivedData directory and measuring the time it takes compared to the previous sequential implementation.

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PR created automatically by Jules for task 6086645156081242781 started by @acebytes

[google-labs-jules]

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[acebytes]

Duplicate of #257 — same nonisolated removeContents + sliding-window TaskGroup pattern in CacheCleaner. #257 is the cleanest variant (no unnecessary inner Task.detached wrapping, which #257's own .jules note correctly identifies as pointless for cooperative-pool work).

[google-labs-jules]

Duplicate of #257 — same nonisolated removeContents + sliding-window TaskGroup pattern in CacheCleaner. #257 is the cleanest variant (no unnecessary inner Task.detached wrapping, which #257's own .jules note correctly identifies as pointless for cooperative-pool work).

Understood. Acknowledging that this work is a duplicate of #257 and stopping work on this task.