feat: Add debug apk build workflow

.github/workflows/debug_build.yml

@@ -0,0 +1,62 @@
+name: Build debug APK
+on:
+  push:
+    branches:
+      - '**'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Cache Gradle
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', '**/buildSrc/**/*.kt') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Setup JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: 17
+          distribution: "temurin"
+          cache: gradle
+
+      - name: Setup Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+
+      - name: Generate Keystore file
+        run: |
+          echo "$KEYSTORE" > ./keystore.b64
+          base64 -d -i ./keystore.b64 > ./keystore.jks
+        env:
+          KEYSTORE: ${{ secrets.RELEASE_KEYSTORE }}
+
+      - name: Generate local.properties
+        run: |
+          echo localKeyPassword=\"$KEY_PASSWORD\" >> local.properties
+          echo localKeyAlias=\"$KEY_ALIAS\" >> local.properties
+          echo localStoreFile=\"../keystore.jks\" >> local.properties
+          echo localStorePassword=\"$STORE_PASSWORD\" >> local.properties
+        shell: bash
+        env:
+          STORE_PASSWORD: ${{ secrets.RELEASE_PASSWORD }}
+          KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
+          KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
+
+      - name: Build debug APK
+        run: ./gradlew assembleDebug
+
+      - name: Upload debug APK
+        uses: actions/upload-artifact@v4
+        with:
+          name: Koreatech-Board-${{ github.ref_name }}-debug.apk
+          path: app/build/outputs/apk/debug/app-debug.apk