[Catalyst] Introduce SettingsContract file

The new file contains all contract constants for external usages (e.g.
slice, external Get/Set API). Also reuse existing constants in
SettingsSlicesContract.

NO_IFTTT=Catalyst only

Bug: 388061003
Flag: EXEMPT refactor
Test: atest
Change-Id: I449b7b6cf82e1e102f2c96a21835191605f09943

src/com/android/settings/contract/SettingsContract.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.contract
+
+import android.provider.SettingsSlicesContract
+
+/** Contract key for the "Airplane Mode" setting. */
+const val KEY_AIRPLANE_MODE = SettingsSlicesContract.KEY_AIRPLANE_MODE
+
+/** Contract key for the "Battery Saver" setting. */
+const val KEY_BATTERY_SAVER = SettingsSlicesContract.KEY_BATTERY_SAVER
+
+/** Contract key for the "Bluetooth" setting. */
+const val KEY_BLUETOOTH = SettingsSlicesContract.KEY_BLUETOOTH
+
+/** Contract key for the "Location" setting. */
+const val KEY_LOCATION = SettingsSlicesContract.KEY_LOCATION
+
+/** Contract key for the "Wi-fi" setting. */
+const val KEY_WIFI = SettingsSlicesContract.KEY_WIFI