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/domain/entities/track.rs

@@ -47,4 +47,20 @@ impl Track {
             Track::Subtitle(t) => t.language = language,
         }
     }
+
+    /// Retorna o fator de escala temporal da faixa.
+    pub fn drift_scale(&self) -> f64 {
+        match self {
+            Track::Audio(t) => t.drift_scale,
+            Track::Subtitle(t) => t.drift_scale,
+        }
+    }
+
+    /// Define o fator de escala temporal da faixa.
+    pub fn set_drift_scale(&mut self, scale: f64) {
+        match self {
+            Track::Audio(t) => t.drift_scale = scale,
+            Track::Subtitle(t) => t.drift_scale = scale,
+        }
+    }
 }