feat: camera-restore + LauncherUI UX 개선 + player fallback 강화 (#15)

camera-restore:
- IEngineStateProvider.SetCamera 반사 쓰기 (HmegDirectStateProvider)
- POST /camera/restore (BridgeHttpServer, StateRouter)
- Recorder --sidecar-url + camera_snapshot 캡처
- UiaPlayerHost.TryRestoreCamera, PlayerEngine 재생 전 복원
- 149 tests

LauncherUI (#15):
- Sidecar URL 체크박스 + 입력란 (녹화/재생 모두 연동)
- 재생 속도 슬라이더 (0.25x~4.0x, 기본 1.0x)
- 빌드 타임스탬프 타이틀바 표시
- 녹화 완료 후 RecordNameBox 초기화
- UiAnalysisWindow 추가

PlayerEngine (#15):
- CancellationToken 지원 (중단 버튼 동작)
- Focus 스텝 early return (no-op, issue #11)
- Type/Drag unresolvable UIA path fallback
- SpeedMultiplier 옵션

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

tests/Recordingtest.Player.Tests/FakePlayerHost.cs

@@ -37,4 +37,14 @@ internal sealed class FakePlayerHost : IPlayerHost
         Failures.Add((stepIndex, reason));
     public List<TimeSpan> Delays { get; } = new();
     public void Delay(TimeSpan duration) => Delays.Add(duration);
+
+    // Camera restore tracking
+    public record CameraRestoreCall(double[] Eye, double[] Target, double[] Up, double Fov);
+    public List<CameraRestoreCall> CameraRestoreCalls { get; } = new();
+    public bool CameraRestoreResult { get; set; } = true;
+    public bool TryRestoreCamera(double[] eye, double[] target, double[] up, double fov)
+    {
+        CameraRestoreCalls.Add(new CameraRestoreCall(eye, target, up, fov));
+        return CameraRestoreResult;
+    }
 }