Move size-tiered and count-based throttling into progressutil.
Localize hardcoded Chinese progress strings.
Drop five duplicated implementations and dead local copies.
Use the resource fingerprint as the dedup key on insert and delete.
Check and set processing entries atomically instead of TOCTOU.
Count only successful downloads.
- Implemented a new task type for handling direct links downloads.
- Added command handler for downloading multiple links via /dl command.
- Introduced progress tracking for direct link downloads.
- Enhanced filename parsing to support various encoding scenarios.
- Updated enums to include direct links as a task type.
- Refactored existing task structures to accommodate new functionality.
- Improved error handling and logging throughout the download process.
