⚡ Bolt: Wrap blocking PIL image operations in asyncio.to_thread

[davidjuarezdev]

💡 What: Wrapped the synchronous downscale_image function calls in await asyncio.to_thread within streamrip/media/artwork.py. This function uses the PIL.Image library for CPU/IO-bound processing (Image.open, image.resize, image.save).
🎯 Why: PIL.Image operations are synchronous and blocking. Calling them directly inside the async def download_artwork function blocked the main asyncio event loop, causing performance bottlenecks and stalling other concurrent download tasks when processing high-resolution artwork or embedding multiple images.
📊 Impact: Eliminates event loop stalls during artwork processing, significantly improving concurrent download performance when handling large albums or playlists.
🔬 Measurement: Verify by downloading an album with large artwork (rip url ... with --config.artwork.embed true and --config.artwork.save_artwork true) and monitoring CPU/asyncio execution flow.

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PR created automatically by Jules for task 11033434195393069513 started by @davidjuarezdev