REUSE compliance [1/*]

Resolve license and copyright issues for all files other than the "app/" module

Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>

.gitignore

@@ -1,3 +1,8 @@
+#
+# SPDX-FileCopyrightText: 2021-2025 Aurora OSS
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
 # Built application files
 *.apk
 *.ap_
@@ -47,4 +52,4 @@ signing.properties
 *.keystore
 
 
-.kotlin/*
+.kotlin/*