feat: add AdjustExistingTrackDrift use case to adjust drift scale of existing tracks

- 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.

src/ui/components/add_audio_track_form.rs

@@ -10,6 +10,8 @@ pub struct AddAudioTrackRequest {
     pub language: TrackLanguage,
     pub is_default: bool,
     pub title: String,
+    /// Fator de escala temporal (correção de drift). 1.0 = sem correção.
+    pub drift_scale: f64,
 }
 
 /// Formulário para adicionar uma faixa de áudio externa.
@@ -33,7 +35,7 @@ impl AddAudioTrackForm {
     }
 
     /// Renderiza o formulário. Retorna `Some(request)` ao confirmar.
-    pub fn ui(&mut self, ui: &mut egui::Ui) -> Option<AddAudioTrackRequest> {
+    pub fn ui(&mut self, ui: &mut egui::Ui, mkvmerge_available: bool) -> Option<AddAudioTrackRequest> {
         let mut result = None;
 
         ui.group(|ui| {
@@ -51,7 +53,7 @@ impl AddAudioTrackForm {
                 }
             });
 
-            self.offset_field.ui(ui, "Atraso:");
+            self.offset_field.ui_with_drift(ui, "Atraso:", mkvmerge_available);
             self.language_field.ui(ui);
 
             ui.horizontal(|ui| {
@@ -82,12 +84,14 @@ impl AddAudioTrackForm {
                     self.offset_field.parse(),
                     self.language_field.parse(),
                 ) {
+                    let drift_scale = self.offset_field.parse_drift();
                     result = Some(AddAudioTrackRequest {
                         path,
                         offset,
                         language,
                         is_default: self.is_default,
                         title: self.title_input.trim().to_string(),
+                        drift_scale,
                     });
                     // Reset form
                     self.selected_path = None;