Implement delayed thumbnail extraction queue

[google-labs-jules]

This change implements a mechanism to trigger background thumbnail extraction when a thumbnail is retrieved via filename fallback (fuzzy match) instead of an exact filepath match.

1. Modified getQuickThumbnailForZip in packages/backend/src/services/thumbnail-query.js to return isFromFileName status.
2. Updated getQuickThumbnail to propagate this status.
3. Updated packages/backend/src/app.js to initialize a thumbnailCorrectionQueue using p-limit.
4. In the /api/thumbnail/get route, if a thumbnail is found via filename fallback, a task is scheduled in the queue (after a delay) to run extractThumbnailFromZip, ensuring the correct thumbnail is generated for future use.

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PR created automatically by Jules for task 14957019630250576712 started by @hjyssg

[google-labs-jules]

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