CI: GitHub Actions workflow to auto-build signed Android APK on tag push

On every v*.*.* tag push the workflow:
  1. Checks out the repo
  2. Sets up JDK 17 + Node 20 + Android SDK (cached between runs)
  3. Runs npm install + npx cap sync android in mobile/
  4. Restores the signing keystore from ANDROID_KEYSTORE_BASE64 secret
  5. Builds a signed release APK via gradle
  6. Renames to pedscribe-X.Y.Z.apk
  7. Creates/updates the matching GitHub release with the APK attached
     and make_latest=true so the /releases/latest URL always points to
     the newest build (Obtanium and the login-page link pick it up
     automatically)

Required repo secrets (set via gh secret set ... or the GitHub UI):
  ANDROID_KEYSTORE_BASE64   base64 -w0 of the .jks file
  ANDROID_KEYSTORE_PASSWORD keystore password
  ANDROID_KEY_ALIAS         key alias (pedscribe)
  ANDROID_KEY_PASSWORD      key password (same as keystore in our setup)

Typical release flow after this lands:
  scripts/release.sh 6.1.1 --push      (laptop, 5 sec)
  ── Actions builds APK in ~8-10 min ──
  ── Release updates automatically with signed APK ──
  ── Obtanium clients notice on next poll ──

.github/workflows/android-release.yml

@@ -0,0 +1,116 @@
+name: Build & release Android APK
+
+# Fires whenever a semver tag is pushed (e.g. v6.1.1). Use
+# scripts/release.sh <version> --push from your laptop to mint the
+# tag; this workflow does everything downstream.
+on:
+  push:
+    tags:
+      - 'v[0-9]+.[0-9]+.[0-9]+'
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Manual tag to build (e.g. v6.1.1)'
+        required: true
+
+permissions:
+  contents: write   # needed to create GitHub releases from the runner
+
+jobs:
+  build:
+    name: Build signed APK
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Resolve tag
+        id: tag
+        run: |
+          TAG="${GITHUB_REF_NAME}"
+          if [[ -z "$TAG" || "$TAG" == "main" ]]; then
+            TAG="${{ github.event.inputs.version }}"
+          fi
+          echo "tag=$TAG" >> "$GITHUB_OUTPUT"
+          echo "version=${TAG#v}" >> "$GITHUB_OUTPUT"
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '17'
+
+      - name: Set up Node 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: npm
+          cache-dependency-path: mobile/package-lock.json
+
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Cache Gradle packages
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: gradle-${{ runner.os }}-${{ hashFiles('mobile/android/**/*.gradle*', 'mobile/android/gradle/wrapper/gradle-wrapper.properties') }}
+          restore-keys: gradle-${{ runner.os }}-
+
+      - name: Install Capacitor + sync
+        working-directory: mobile
+        run: |
+          npm install --no-audit --no-fund
+          npx cap sync android
+
+      - name: Restore keystore from secret
+        env:
+          KEYSTORE_B64: ${{ secrets.ANDROID_KEYSTORE_BASE64 }}
+        run: |
+          echo "$KEYSTORE_B64" | base64 -d > $RUNNER_TEMP/pedscribe-release.jks
+          ls -la $RUNNER_TEMP/pedscribe-release.jks
+
+      - name: Build signed release APK
+        working-directory: mobile/android
+        env:
+          KS_PASS:  ${{ secrets.ANDROID_KEYSTORE_PASSWORD }}
+          KEY_ALIAS: ${{ secrets.ANDROID_KEY_ALIAS }}
+          KEY_PASS:  ${{ secrets.ANDROID_KEY_PASSWORD }}
+        run: |
+          ./gradlew assembleRelease \
+            -Pandroid.injected.signing.store.file=$RUNNER_TEMP/pedscribe-release.jks \
+            -Pandroid.injected.signing.store.password="$KS_PASS" \
+            -Pandroid.injected.signing.key.alias="$KEY_ALIAS" \
+            -Pandroid.injected.signing.key.password="$KEY_PASS" \
+            --no-daemon --stacktrace
+
+      - name: Locate APK
+        id: apk
+        run: |
+          APK=$(find mobile/android/app/build/outputs/apk/release -name '*.apk' | head -1)
+          test -n "$APK" || { echo "no APK found"; exit 1; }
+          echo "path=$APK" >> "$GITHUB_OUTPUT"
+          echo "found: $APK ($(stat -c%s "$APK") bytes)"
+
+      - name: Rename APK with version
+        id: rename
+        run: |
+          DST="pedscribe-${{ steps.tag.outputs.version }}.apk"
+          cp "${{ steps.apk.outputs.path }}" "$DST"
+          echo "path=$DST" >> "$GITHUB_OUTPUT"
+
+      - name: Create or update GitHub release
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ steps.tag.outputs.tag }}
+          name: PedScribe ${{ steps.tag.outputs.version }}
+          make_latest: 'true'
+          generate_release_notes: true
+          files: |
+            ${{ steps.rename.outputs.path }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}