build: enable app shrinking for release build type

app/build.gradle.kts

@@ -38,8 +38,12 @@ android {
 
     buildTypes {
         release {
-            isMinifyEnabled = false
-            // proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-android.txt"
+            isMinifyEnabled = true
+            isShrinkResources = true
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro",
+            )
             signingConfig =
                 project.signKeyFile?.let {
                     signingConfigs.create("release") {

app/proguard-rules.pro

@@ -0,0 +1,31 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# disable obfuscation
+-dontobfuscate
+
+# Keep JNI interface
+-keep class com.osfans.trime.core.* { *; }
+
+# remove kotlin null checks
+-assumenosideeffects class kotlin.jvm.internal.Intrinsics {
+    static void checkNotNull(...);
+    static void checkExpressionValueIsNotNull(...);
+    static void checkNotNullExpressionValue(...);
+    static void checkReturnedValueIsNotNull(...);
+    static void checkFieldIsNotNull(...);
+    static void checkParameterIsNotNull(...);
+    static void checkNotNullParameter(...);
+}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile