chore(build): add release keystore and configure signing for all build types

V2rayNG/app/build.gradle.kts

@@ -38,13 +38,26 @@ android {
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
 
+    signingConfigs {
+        create("release") {
+            storeFile = file("${rootProject.projectDir}/release.keystore")
+            storePassword = "android"
+            keyAlias = "v2rayng"
+            keyPassword = "android"
+        }
+    }
+
     buildTypes {
+        debug {
+            signingConfig = signingConfigs.getByName("release")
+        }
         release {
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
             )
+            signingConfig = signingConfigs.getByName("release")
         }
     }
 
@@ -52,7 +65,6 @@ android {
     productFlavors {
         create("fdroid") {
             dimension = "distribution"
-            applicationIdSuffix = ".fdroid"
             buildConfigField("String", "DISTRIBUTION", "\"F-Droid\"")
         }
         create("playstore") {