feat: implement SMSG_CAMERA_SHAKE with sinusoidal camera shake effect

- Add triggerShake(magnitude, frequency, duration) to CameraController
- Apply envelope-decaying sinusoidal XYZ offset to camera in update()
- Handle SMSG_CAMERA_SHAKE opcode in GameHandler dispatch
- Translate shakeId to magnitude (minor <50: 0.04, larger: 0.08 world units)
- Wire CameraShakeCallback from GameHandler through to CameraController
- Shake uses 18Hz oscillation with 30% fade-out envelope at end of duration

src/core/application.cpp

@@ -646,6 +646,11 @@ void Application::setState(AppState newState) {
                         renderer->getCameraController()->applyKnockBack(vcos, vsin, hspeed, vspeed);
                     }
                 });
+                gameHandler->setCameraShakeCallback([this](float magnitude, float frequency, float duration) {
+                    if (renderer && renderer->getCameraController()) {
+                        renderer->getCameraController()->triggerShake(magnitude, frequency, duration);
+                    }
+                });
             }
             // Load quest marker models
             loadQuestMarkerModels();