Add voiding diary view + home icon navigation

VoidingDiaryView:
- Date-grouped record list (grouped by day)
- Shows volume/awake/sleep with icons and colors
- Method badge (수기/음성/카메라)
- Delete with confirmation dialog
- Total record count footer

Navigation changes:
- Piezo screen: ArrowBack → Home icon (집 아이콘)
- Piezo screen: 배뇨일지 icon (Description) added next to home
- NIRS screen: ArrowBack → Home icon
- AppScreen.VOIDING_DIARY route added to Crossfade navigation
- VoidingDiaryView navigates back to HOME

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/example/medilightv2android/MainActivity.kt

@@ -23,6 +23,7 @@ import com.example.medilightv2android.ui.views.history.MeasurementHistoryView
 import com.example.medilightv2android.ui.views.home.HomeView
 import com.example.medilightv2android.ui.views.monitoring.PiezoMonitoringView
 import com.example.medilightv2android.ui.views.monitoring.VivamyoMonitoringView
+import com.example.medilightv2android.ui.views.monitoring.VoidingDiaryView
 import com.example.medilightv2android.ui.views.onboarding.OnboardingView
 import com.example.medilightv2android.ui.views.personalization.PiezoPersonalizationView
 import com.example.medilightv2android.ui.views.pin.PinMode
@@ -74,6 +75,7 @@ fun MedilightApp(modifier: Modifier = Modifier) {
             AppScreen.VIVAMYO_MONITORING -> VivamyoMonitoringView(appState)
             AppScreen.PIEZO_MONITORING -> PiezoMonitoringView(appState)
             AppScreen.MEASUREMENT_HISTORY -> MeasurementHistoryView(appState)
+            AppScreen.VOIDING_DIARY -> VoidingDiaryView(onBack = { appState.currentScreen = AppScreen.HOME })
         }
     }
 }