Add release signing, versioning and dist task

- Version defined once; versionCode = MAJOR*10000 + MINOR*100 + PATCH
- Optional release signing from ~/.gradle/gradle.properties
- ./gradlew dist copies signed APKs to dist/ with Obtainium-friendly names

Co-Authored-By: Claude Opus 5.5 <[email protected]>

app/build.gradle.kts

@@ -4,13 +4,31 @@ plugins {
     alias(libs.plugins.pixelwall.android.hilt)
 }
 
+// Einzige Quelle der Version. versionCode = MAJOR*10000 + MINOR*100 + PATCH (streng monoton für Obtainium).
+val appVersion = "0.1.0"
+val appVersionCode = appVersion.split(".").map(String::toInt).let { (major, minor, patch) -> major * 10000 + minor * 100 + patch }
+
+// Release-Signatur aus ~/.gradle/gradle.properties; fehlt sie, entstehen unsignierte APKs (z. B. für F-Droid).
+val signingStoreFile = providers.gradleProperty("pixelwall.signing.storeFile").orNull
+
 android {
     namespace = "org.pixelwall.app"
 
     defaultConfig {
         applicationId = "org.pixelwall.app"
-        versionCode = 1
-        versionName = "0.1.0"
+        versionCode = appVersionCode
+        versionName = appVersion
+    }
+
+    signingConfigs {
+        if (signingStoreFile != null) {
+            create("release") {
+                storeFile = file(signingStoreFile)
+                storePassword = providers.gradleProperty("pixelwall.signing.storePassword").get()
+                keyAlias = providers.gradleProperty("pixelwall.signing.keyAlias").get()
+                keyPassword = providers.gradleProperty("pixelwall.signing.keyPassword").get()
+            }
+        }
     }
 
     flavorDimensions += "network"
@@ -33,6 +51,7 @@ android {
             isMinifyEnabled = true
             isShrinkResources = true
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+            signingConfig = signingConfigs.findByName("release")
         }
     }
 
@@ -47,6 +66,21 @@ android {
     }
 }
 
+// Release-APKs mit stabilen Namen für Gitea-Releases/Obtainium nach dist/ kopieren.
+val dist = tasks.register<Sync>("dist") {
+    description = "Copies signed release APKs to dist/ as pixelwall-<flavor>-v<version>.apk"
+    dependsOn("assembleCoreRelease", "assembleFullRelease")
+    val version = appVersion // lokale Kopie: Lambdas dürfen keine Skript-Objekte referenzieren (Configuration Cache)
+    for (flavor in listOf("core", "full")) {
+        val apkName = "pixelwall-$flavor-v$version.apk"
+        from(layout.buildDirectory.dir("outputs/apk/$flavor/release")) {
+            include("*.apk")
+            rename { apkName }
+        }
+    }
+    into(rootProject.layout.projectDirectory.dir("dist"))
+}
+
 dependencies {
     implementation(project(":core:model"))
     implementation(project(":core:domain"))