chore: add license headers to Kotlin sources

Author: whalechoi

app/src/main/kotlin/app/AsteriskApplication.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package app
 
 import android.app.Application

app/src/main/kotlin/app/MainActivity.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package app
 
 import android.Manifest

app/src/main/kotlin/app/modes/AppModes.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package app.modes
 
 const val RunModeVpnService = 0

app/src/main/kotlin/app/modes/UiModes.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package app.modes
 
 const val ColorModeSystem = 0

app/src/main/kotlin/data/AndroidAppStateStore.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import android.content.Context

app/src/main/kotlin/data/AppSettingsPreferences.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import android.content.Context

app/src/main/kotlin/data/AppStateDao.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import androidx.room.Dao

app/src/main/kotlin/data/AppStateJson.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import app.CustomResourceFileState

app/src/main/kotlin/data/AsteriskAppDatabase.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import androidx.room.Database

app/src/main/kotlin/data/ListEntities.kt

@@ -1,3 +1,6 @@
+// Copyright 2026, AsteriskNG contributors
+// SPDX-License-Identifier: GPL-3.0
+
 package data
 
 import androidx.room.Entity