Add consistent APK signing so updates install without uninstalling

- Generate pixel10.keystore and store as KEYSTORE_BASE64 GitHub secret
- Release workflow decodes keystore and signs every APK with same key
- build.gradle.kts: signingConfig reads from env (CI) or local keystore
- Bump versionCode 8 / versionName 1.8.0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -30,7 +30,16 @@ jobs:
           key: gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
           restore-keys: gradle-
 
-      - name: Build debug APK
+      - name: Decode signing keystore
+        run: |
+          echo "${{ secrets.KEYSTORE_BASE64 }}" | base64 -d > "$RUNNER_TEMP/pixel10.keystore"
+
+      - name: Build signed debug APK
+        env:
+          KEYSTORE_PATH: ${{ runner.temp }}/pixel10.keystore
+          KEYSTORE_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
+          KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
+          KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
         run: ./gradlew assembleDebug --no-daemon
 
       - name: Rename APK with version tag

.gitignore

@@ -15,3 +15,4 @@ local.properties
 *.bin
 *.task
 *.tflite
+pixel10.keystore

app/build.gradle.kts

@@ -11,8 +11,27 @@ android {
         applicationId = "com.pixel10.ai"
         minSdk = 31
         targetSdk = 35
-        versionCode = 7
-        versionName = "1.7.0"
+        versionCode = 8
+        versionName = "1.8.0"
+    }
+
+    val keystoreFile = rootProject.file("pixel10.keystore")
+    val keystoreEnv = System.getenv("KEYSTORE_PATH")
+
+    signingConfigs {
+        create("release") {
+            if (keystoreEnv != null) {
+                storeFile = file(keystoreEnv)
+                storePassword = System.getenv("KEYSTORE_PASSWORD")
+                keyAlias = System.getenv("KEY_ALIAS")
+                keyPassword = System.getenv("KEY_PASSWORD")
+            } else if (keystoreFile.exists()) {
+                storeFile = keystoreFile
+                storePassword = "pixel10ai"
+                keyAlias = "pixel10"
+                keyPassword = "pixel10ai"
+            }
+        }
     }
 
     buildTypes {
@@ -22,6 +41,16 @@ android {
                 getDefaultProguardFile("proguard-android-optimize.txt"),
                 "proguard-rules.pro"
             )
+            val releaseSigning = signingConfigs.getByName("release")
+            if (releaseSigning.storeFile != null) {
+                signingConfig = releaseSigning
+            }
+        }
+        debug {
+            val releaseSigning = signingConfigs.getByName("release")
+            if (releaseSigning.storeFile != null) {
+                signingConfig = releaseSigning
+            }
         }
     }