feat(widget): Add ANC control widget

New home-screen widget that toggles AirPods ANC modes (Off / ANC / Transparency / Adaptive) directly, with six adaptive layouts that pick based on widget size (QUAD_CORNERS, ROW_ICONS, COLUMN_ICONS, GRID_2X2, ROW, COLUMN). Consolidated battery+ANC configuration into a single ViewModel that detects widget type from AppWidgetManager. ACTIVE state uses Material3 secondaryContainer/onSecondaryContainer for guaranteed contrast. Includes live config preview, preview subtitle, stale-selection guard, device-label toggle, and aligned icons with the app's AncModeSelector.

app/src/main/AndroidManifest.xml

@@ -101,6 +101,17 @@
                 android:resource="@xml/battery_widget_info" />
         </receiver>
 
+        <receiver
+            android:name=".main.ui.widget.AncWidgetProvider"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/anc_widget_info" />
+        </receiver>
+
         <provider
             android:name="androidx.core.content.FileProvider"
             android:authorities="${applicationId}.provider"