WCAG: Add reduce_motion config, bridge property, OS detection

Config default, reduceMotion Q_PROPERTY on UIBridge, Windows
SystemParametersInfo detection for prefers-reduced-motion.

src/ui/bridge.py

@@ -111,6 +111,7 @@ class UIBridge(QObject):
     settingChanged = Signal(str, 'QVariant')
     modelStatesChanged = Signal() # Notify UI to re-check isModelDownloaded
     llmDownloadRequested = Signal()
+    reduceMotionChanged = Signal(bool)
 
     def __init__(self, parent=None):
         super().__init__(parent)
@@ -130,6 +131,7 @@ class UIBridge(QObject):
         self._app_vram_mb = 0.0
         self._app_vram_percent = 0.0
         self._is_destroyed = False
+        self._reduce_motion = bool(ConfigManager().get("reduce_motion"))
         
         # Start QThread Stats Worker
         self.stats_worker = StatsWorker()
@@ -277,6 +279,8 @@ class UIBridge(QObject):
         ConfigManager().set(key, value)
         if key == "ui_scale":
             self.uiScale = float(value)
+        if key == "reduce_motion":
+            self.reduceMotion = bool(value)
         self.settingChanged.emit(key, value) # Notify listeners (e.g. Overlay)
         
     @Property(float, notify=uiScaleChanged)
@@ -288,6 +292,15 @@ class UIBridge(QObject):
             self._ui_scale = val
             self.uiScaleChanged.emit(val)
 
+    @Property(bool, notify=reduceMotionChanged)
+    def reduceMotion(self): return self._reduce_motion
+
+    @reduceMotion.setter
+    def reduceMotion(self, val):
+        if self._reduce_motion != val:
+            self._reduce_motion = val
+            self.reduceMotionChanged.emit(val)
+
     @Property(float, notify=appCpuChanged)
     def appCpu(self): return self._app_cpu