Add download limit feature to shares and update related UI components

[Thnorty]

This PR introduces the missing functionality to set a maximum download limit when creating file shares, making it work seamlessly alongside the existing time based expiration feature.

Changes:

• Uploader UI: Added a numeric input to the share creation panel allowing users to set a specific download limit (defaults to "Unlimited").
• Downloader UI: Added a live tracker below the expiration timer showing remaining downloads (e.g., "Downloaded 1 of 3 times").
• Enforcement: SharesController.php now blocks access and automatically sets the share's expires_at to Carbon::now() the moment the limit is hit.
• Cleanup: By forcing the expiration date, this feature natively hooks into the existing cleanExpiredShares job to physically delete the files without needing new cleanup logic.
• Translations: Added localization strings across 6 languages for the new UI elements.

Testing:
Create a share with a set download limit. Download it until the limit is exhausted; the share should immediately invalidate and reflect as expired.