feat: Add Camera Settings dialog for UVC controls and Qt parameters

- Implemented CameraSettingsDialog to manage UVC and Qt camera controls.
- Integrated UVC parameter sliders and auto controls for brightness, contrast, saturation, hue, sharpness, gamma, white balance, backlight compensation, and exposure.
- Added functionality to change white balance and exposure settings via Qt controls.
- Updated MainWindow to open CameraSettingsDialog and manage UVC controller lifecycle.
- Enhanced AppMenuBar to include a Camera Settings option.
- Created tests for UVC controller abstraction layer and parameter info.
- Documented camera specifications and supported features in new markdown files.

tests/test_uvc.py

@@ -0,0 +1,117 @@
+"""Tests for the UVC controller abstraction layer."""
+
+from __future__ import annotations
+
+from app.camera.uvc.base import UvcParam, UvcParamInfo
+from app.camera.uvc.stub import NullUvcController
+
+
+class TestNullUvcController:
+    """NullUvcController must implement the full interface, all as no-ops."""
+
+    def setup_method(self) -> None:
+        self.ctrl = NullUvcController()
+
+    def test_is_not_open(self) -> None:
+        assert not self.ctrl.is_open()
+
+    def test_open_returns_false(self) -> None:
+        assert self.ctrl.open("any device") is False
+
+    def test_close_does_not_raise(self) -> None:
+        self.ctrl.close()  # must not raise
+
+    def test_get_param_info_returns_unsupported(self) -> None:
+        info = self.ctrl.get_param_info(UvcParam.BRIGHTNESS)
+        assert isinstance(info, UvcParamInfo)
+        assert info.supported is False
+        assert info.param is UvcParam.BRIGHTNESS
+
+    def test_get_all_params_covers_all_uvc_params(self) -> None:
+        infos = self.ctrl.get_all_params()
+        returned_params = {i.param for i in infos}
+        all_params = set(UvcParam)
+        assert returned_params == all_params
+
+    def test_get_all_params_all_unsupported(self) -> None:
+        for info in self.ctrl.get_all_params():
+            assert info.supported is False
+
+    def test_set_value_returns_false(self) -> None:
+        assert self.ctrl.set_value(UvcParam.CONTRAST, 50) is False
+
+    def test_set_auto_returns_false(self) -> None:
+        assert self.ctrl.set_auto(UvcParam.WHITE_BALANCE, True) is False
+
+    def test_set_value_does_not_raise(self) -> None:
+        for param in UvcParam:
+            self.ctrl.set_value(param, 0)  # must not raise
+
+    def test_set_auto_does_not_raise(self) -> None:
+        for param in UvcParam:
+            self.ctrl.set_auto(param, True)   # must not raise
+            self.ctrl.set_auto(param, False)
+
+
+class TestUvcParamInfo:
+    """UvcParamInfo dataclass sanity checks."""
+
+    def test_defaults(self) -> None:
+        info = UvcParamInfo(param=UvcParam.BRIGHTNESS, supported=True)
+        assert info.minimum == 0
+        assert info.maximum == 100
+        assert info.default == 50
+        assert info.current == 50
+        assert info.step == 1
+        assert info.auto_supported is False
+        assert info.auto_enabled is False
+
+    def test_unsupported_flag(self) -> None:
+        info = UvcParamInfo(param=UvcParam.GAMMA, supported=False)
+        assert info.supported is False
+
+    def test_custom_range(self) -> None:
+        info = UvcParamInfo(
+            param=UvcParam.HUE,
+            supported=True,
+            minimum=-180,
+            maximum=180,
+            default=0,
+            current=-45,
+        )
+        assert info.minimum == -180
+        assert info.maximum == 180
+        assert info.current == -45
+
+
+class TestMakeUvcControllerFallback:
+    """make_uvc_controller falls back to NullUvcController when no lib available."""
+
+    def test_returns_controller_instance(self) -> None:
+        from app.camera.uvc import make_uvc_controller
+        from app.camera.uvc.base import UvcControllerBase
+        ctrl = make_uvc_controller("Test Camera")
+        assert isinstance(ctrl, UvcControllerBase)
+
+    def test_stub_used_when_native_lib_absent(self, monkeypatch) -> None:
+        """If the native import fails, should return NullUvcController."""
+        import builtins
+        real_import = builtins.__import__
+
+        def patched_import(name, *args, **kwargs):
+            if name in ("duvc_ctl", "uvc"):
+                raise ImportError(f"Mocked missing: {name}")
+            return real_import(name, *args, **kwargs)
+
+        monkeypatch.setattr(builtins, "__import__", patched_import)
+        # Re-import to exercise factory with patched import
+        import importlib
+
+        import app.camera.uvc as uvc_pkg
+        importlib.reload(uvc_pkg)
+        ctrl = uvc_pkg.make_uvc_controller("Test Camera")
+        # Should be functional (not raise), may be Null or platform controller
+        from app.camera.uvc.base import UvcControllerBase
+        assert isinstance(ctrl, UvcControllerBase)
+        # Reload back to normal
+        importlib.reload(uvc_pkg)