Fix camera screen: navigate via AppScreen instead of overlay

Camera was hidden behind PiezoMonitoringView because it was rendered
as a child composable. Now uses AppScreen.URINE_CAMERA for full
Crossfade navigation — camera gets its own screen transition.

Flow: Catheterize → 카메라 → AppScreen.URINE_CAMERA → measure → back to PIEZO_MONITORING

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

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

@@ -14,7 +14,8 @@ enum class AppScreen {
     ONBOARDING, REGISTRATION, HOME, SENSOR_SELECT, DEVICE_SCAN,
     NIRS_CALIBRATION, PIEZO_PERSONALIZATION, PIN_SETUP, PIN_ENTRY,
     VIVAMYO_MONITORING, PIEZO_MONITORING, MEASUREMENT_HISTORY,
-    VOIDING_DIARY
+    VOIDING_DIARY,
+    URINE_CAMERA
 }
 
 class AppState(private val context: Context) {

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.UrineCameraScreen
 import com.example.medilightv2android.ui.views.monitoring.VoidingDiaryView
 import com.example.medilightv2android.ui.views.onboarding.OnboardingView
 import com.example.medilightv2android.ui.views.personalization.PiezoPersonalizationView
@@ -76,6 +77,13 @@ fun MedilightApp(modifier: Modifier = Modifier) {
             AppScreen.PIEZO_MONITORING -> PiezoMonitoringView(appState)
             AppScreen.MEASUREMENT_HISTORY -> MeasurementHistoryView(appState)
             AppScreen.VOIDING_DIARY -> VoidingDiaryView(onBack = { appState.currentScreen = AppScreen.HOME })
+            AppScreen.URINE_CAMERA -> UrineCameraScreen(
+                onDone = { volume ->
+                    if (volume != null && volume > 0) appState.resetLevel()
+                    appState.currentScreen = AppScreen.PIEZO_MONITORING
+                },
+                onCancel = { appState.currentScreen = AppScreen.PIEZO_MONITORING }
+            )
         }
     }
 }

app/src/main/java/com/example/medilightv2android/ui/views/monitoring/PiezoMonitoringView.kt

@@ -250,15 +250,12 @@ fun PiezoMonitoringView(appState: AppState) {
         )
     }
 
-    // 소변컵 카메라 촬영 화면 (풀스크린 오버레이)
+    // 카메라 → AppScreen으로 전환
+    LaunchedEffect(showUrineCamera) {
         if (showUrineCamera) {
-        UrineCameraScreen(
-            onDone = { volume ->
             showUrineCamera = false
-                if (volume != null && volume > 0) appState.resetLevel()
+            appState.currentScreen = AppScreen.URINE_CAMERA
-            },
+        }
-            onCancel = { showUrineCamera = false }
-        )
     }
 
     Column(