chore(scaffold): M0 Gradle + Compose + Hilt skeleton with CI

Stand up the Android-app repo per docs/android/PLAN.md M0: a buildable
Kotlin + Jetpack Compose (Material 3) single-activity skeleton wired for
Hilt, ready for the M1-M4 functional pass.

- Gradle 8.7 wrapper; AGP 8.6.1 / Kotlin 2.0.20, JDK 17, minSdk 29, target 35.
- Version catalog (gradle/libs.versions.toml) pins the full planned stack
  (Compose, Hilt, Retrofit/OkHttp + kotlinx.serialization, DataStore,
  security-crypto, Coil, Navigation) so later milestones reference by alias.
- RunicGatewayApp (@HiltAndroidApp) + MainActivity (Compose) + ui/theme/*.
- Strings externalized from day one; adaptive launcher icon; backup rules
  exclude the token store / DataStore (no session material off-device).
- CI: .gitea/workflows/pr-checks.yml gates PRs with lint + test + assembleDebug
  (JDK 17 + Android SDK on the self-hosted runner; debug builds auto-signed,
  no secrets). Placeholder JVM unit test so the test gate runs.
- .gitattributes forces LF on gradlew so the wrapper runs on the Linux runner.

Verified locally: `gradle help`/`projects` configure the :app module and
resolve all six plugins cleanly (full assemble needs the Android SDK, done in CI).

app id: com.runicgateway.app (PLAN.md §13, pending runicgateway.app domain).

Co-Authored-By: Claude <noreply@anthropic.com>

app/build.gradle.kts

@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.ksp)
+    alias(libs.plugins.hilt)
+}
+
+android {
+    namespace = "com.runicgateway.app"
+    compileSdk = 35
+
+    defaultConfig {
+        // Target application id per docs/android/PLAN.md §13 (pending runicgateway.app domain).
+        applicationId = "com.runicgateway.app"
+        minSdk = 29
+        targetSdk = 35
+        versionCode = 1
+        versionName = "0.1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            // Signing/minification are wired at M6 (release hardening). Debug is auto-signed.
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro",
+            )
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = "17"
+    }
+
+    buildFeatures {
+        compose = true
+        buildConfig = true
+    }
+
+    packaging {
+        resources {
+            excludes += "/META-INF/{AL2.0,LGPL2.1}"
+        }
+    }
+}
+
+dependencies {
+    // Core / lifecycle / activity
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.lifecycle.runtime.ktx)
+    implementation(libs.androidx.lifecycle.runtime.compose)
+    implementation(libs.androidx.lifecycle.viewmodel.compose)
+    implementation(libs.androidx.activity.compose)
+
+    // Compose (BOM-managed versions)
+    implementation(platform(libs.androidx.compose.bom))
+    implementation(libs.androidx.compose.ui)
+    implementation(libs.androidx.compose.ui.graphics)
+    implementation(libs.androidx.compose.ui.tooling.preview)
+    implementation(libs.androidx.compose.material3)
+    implementation(libs.androidx.navigation.compose)
+    debugImplementation(libs.androidx.compose.ui.tooling)
+    debugImplementation(libs.androidx.compose.ui.test.manifest)
+
+    // DI
+    implementation(libs.hilt.android)
+    ksp(libs.hilt.compiler)
+    implementation(libs.androidx.hilt.navigation.compose)
+
+    // Networking (wired for M1+; declared now so the stack resolves)
+    implementation(libs.retrofit)
+    implementation(platform(libs.okhttp.bom))
+    implementation(libs.okhttp)
+    implementation(libs.okhttp.logging.interceptor)
+    implementation(libs.okhttp.sse)
+    implementation(libs.kotlinx.serialization.json)
+    implementation(libs.retrofit.kotlinx.serialization.converter)
+
+    // Storage
+    implementation(libs.androidx.datastore.preferences)
+    implementation(libs.androidx.security.crypto)
+
+    // Images
+    implementation(libs.coil.compose)
+
+    // Unit tests
+    testImplementation(libs.junit)
+    testImplementation(libs.kotlinx.coroutines.test)
+
+    // Instrumented tests
+    androidTestImplementation(libs.androidx.test.ext.junit)
+    androidTestImplementation(libs.androidx.espresso.core)
+    androidTestImplementation(platform(libs.androidx.compose.bom))
+    androidTestImplementation(libs.androidx.compose.ui.test.junit4)
+}