Add CI/CD workflows and release signing config

Build workflow: runs tests + assembles debug APK on pull requests.
Release workflow: builds signed APK and uploads to GitHub release.
Signing config reads keystore from env vars (set by CI secrets).
Keystore files excluded from git.

Signed-off-by: Avinal Kumar <avinal.xlvii@gmail.com>
Co-Authored-By: Claude Opus 4.6 (1M context)

.github/workflows/build.yml

@@ -0,0 +1,31 @@
+name: Build & Test
+
+on:
+  pull_request:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 17
+
+      - uses: gradle/actions/setup-gradle@v4
+
+      - name: Run tests
+        run: ./gradlew :composeApp:testDebugUnitTest
+
+      - name: Build debug APK
+        run: ./gradlew :androidApp:assembleDebug
+
+      - name: Upload debug APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: debug-apk
+          path: androidApp/build/outputs/apk/debug/*.apk

.github/workflows/release.yml

@@ -0,0 +1,39 @@
+name: Release
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 17
+
+      - uses: gradle/actions/setup-gradle@v4
+
+      - name: Decode keystore
+        run: echo "${{ secrets.KEYSTORE_BASE64 }}" | base64 -d > ${{ runner.temp }}/keystore.jks
+
+      - name: Build signed release APK
+        env:
+          KEYSTORE_PATH: ${{ runner.temp }}/keystore.jks
+          KEYSTORE_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
+          KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
+          KEY_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
+        run: ./gradlew :androidApp:assembleRelease
+
+      - name: Upload release APK
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          mv androidApp/build/outputs/apk/release/androidApp-release.apk nikki-${{ github.event.release.tag_name }}.apk
+          gh release upload ${{ github.event.release.tag_name }} nikki-${{ github.event.release.tag_name }}.apk

.gitignore

@@ -26,6 +26,10 @@ index.html
 script.js
 styles.css
 
+# Signing
+*.jks
+*.keystore
+
 # Dev artifacts
 PLAN.md
 Screenshot_*.png

androidApp/build.gradle.kts

@@ -16,6 +16,18 @@ android {
         versionName = "1.0.0"
     }
 
+    signingConfigs {
+        create("release") {
+            val path = System.getenv("KEYSTORE_PATH")
+            if (path != null) {
+                storeFile = file(path)
+                storePassword = System.getenv("KEYSTORE_PASSWORD")
+                keyAlias = System.getenv("KEY_ALIAS")
+                keyPassword = System.getenv("KEY_PASSWORD")
+            }
+        }
+    }
+
     buildTypes {
         release {
             isMinifyEnabled = true
@@ -23,6 +35,7 @@ android {
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
             )
+            signingConfig = signingConfigs.getByName("release")
         }
     }