- Implemented AdjustExistingTrackDrift struct with execute method to modify drift scale of existing tracks in a project.
- Added tests for adjusting drift scale, handling non-existent track IDs, and invalid scale values.
- Updated MediaTrackInfo and AudioTrack entities to include drift_scale field.
- Enhanced Project entity with needs_mkvmerge method to determine if mkvmerge is required based on drift scale.
- Integrated drift scale adjustments into existing track list UI, allowing users to modify drift values.
- Updated various use cases and UI components to support drift scale functionality, including add audio/subtitle forms and batch processing.
- Implemented mkvmerge availability check and integrated it into the application workflow for conditional processing.
- Added `ActiveTab` enum to manage active tab state in `App`.
- Created `BatchItem` struct and integrated `batch_items` vector in `App`.
- Developed `BatchPanel` component for managing batch projects with inline forms.
- Implemented sequential processing in `App::start_batch_item()` with automatic advancement in `poll_background()`.
- Updated UI to display individual item states (`⏳ Aguardando | ⟳ Processando | ✓ Concluído | ⊸ Cancelado | ✗ Erro`).
- Blocked item addition/removal during processing.
- Enhanced session persistence to include batch projects in `SessionData`.
- Updated session save/load functions to handle new session structure.
Felipe