fix: update default master volume to 1.0

src/constants/coreConstants.ts

@@ -62,7 +62,7 @@ export const KEY_SIGNATURE_MAP = {
 // };
 
 export const AUDIO_INTERFACE_CONSTANTS = {
-  DEFAULT_MASTER_VOLUME: 0.8,
+  DEFAULT_MASTER_VOLUME: 1.0,
   DEFAULT_TRACK_VOLUME: 0,   // 0 dB (unity gain)
   MIN_TRACK_VOLUME_DB: -60,  // practical floor; displayed as −∞
   MAX_TRACK_VOLUME_DB: 12,

src/test/utils/mock-data.ts

@@ -120,7 +120,7 @@ export const createMockMidiTrack = (overrides: Partial<{
     name: 'Test Track',
     id: 0,
     instrument: 'acoustic_grand_piano' as const,
-    volume: 0.8,
+    volume: 0,
     ...overrides
   };
   

src/test/utils/setup-integration-tests.ts

@@ -81,7 +81,7 @@ export const createMockTrack = (name = 'Test Track') => {
     id: `track-${Date.now()}`,
     name,
     instrument: 'acoustic_grand_piano',
-    volume: 0.8,
+    volume: 0,
     regions: [],
   };
 };