Harden CameraManager error handling

- Catch SecurityException separately with permission-specific message
- Replace raw e.message with generic user-friendly error strings
- Wrap cameraProviderFuture.get() in try-catch to handle CameraX
  initialization failures instead of crashing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/main/java/no/naiv/tiltshift/camera/CameraManager.kt

@@ -73,9 +73,14 @@ class CameraManager(private val context: Context) {
 
         val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
         cameraProviderFuture.addListener({
+            try {
                 cameraProvider = cameraProviderFuture.get()
                 lensController.initialize(cameraProvider?.availableCameraInfos ?: emptyList())
                 bindCameraUseCases(lifecycleOwner)
+            } catch (e: Exception) {
+                Log.e(TAG, "CameraX initialization failed", e)
+                _error.value = "Camera could not initialize. Please restart the app."
+            }
         }, ContextCompat.getMainExecutor(context))
     }
 
@@ -129,9 +134,12 @@ class CameraManager(private val context: Context) {
                 provideSurface(request)
             }
 
+        } catch (e: SecurityException) {
+            Log.e(TAG, "Camera permission denied at runtime", e)
+            _error.value = "Camera permission was revoked. Please grant it in Settings."
         } catch (e: Exception) {
             Log.e(TAG, "Camera binding failed", e)
-            _error.value = "Camera failed: ${e.message}"
+            _error.value = "Camera could not start. Please try again or restart the app."
         }
     }