Emphasize the license

backdrop/src/main/java/com/kyant/backdrop/Shaders.kt

@@ -1,3 +1,19 @@
+/*
+   Copyright 2025 Kyant
+
+   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.kyant.backdrop
 
 import org.intellij.lang.annotations.Language