fix(android): make Docker APK build pass with Capacitor config, synced lockfile, and JDK 21

- Track frontend/capacitor.config.json with appId/appName/webDir for Capacitor Android setup
- Unignore frontend/capacitor.config.json so config is committed with the project
- Update Android Docker builder to use JDK 21 (required by current Capacitor/Gradle toolchain)
- Switch Docker CMD to JSON-array form for safer signal handling
- Refresh frontend package-lock.json to match Capacitor and crypto dependencies required by npm ci

.gitignore

@@ -15,6 +15,7 @@ __pycache__/
 !package-lock.json
 !frontend/package.json
 !frontend/package-lock.json
+!frontend/capacitor.config.json
 
 # Frontend build output and dependencies
 node_modules/

contrib/android/Dockerfile

@@ -1,15 +1,20 @@
 FROM node:22.14.0-bookworm
 
-# ── System deps: JDK 17 + tooling ─────────────────────────────────────────────
+# ── System deps + JDK 21 (required by current Capacitor Android toolchain) ───
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    default-jdk \
+    ca-certificates \
     wget unzip \
     && rm -rf /var/lib/apt/lists/*
 
+ENV JAVA_HOME=/opt/java/openjdk
+RUN mkdir -p "${JAVA_HOME}" && \
+    wget -qO- "https://api.adoptium.net/v3/binary/latest/21/ga/linux/x64/jdk/hotspot/normal/eclipse?project=jdk" \
+    | tar -xz -C "${JAVA_HOME}" --strip-components=1
+
 # ── Android SDK command-line tools ────────────────────────────────────────────
 # https://developer.android.com/studio#command-line-tools-only
 ENV ANDROID_SDK_ROOT=/opt/android-sdk
-ENV PATH="${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin:${ANDROID_SDK_ROOT}/platform-tools:${PATH}"
+ENV PATH="${JAVA_HOME}/bin:${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin:${ANDROID_SDK_ROOT}/platform-tools:${PATH}"
 
 RUN mkdir -p "${ANDROID_SDK_ROOT}/cmdline-tools" && \
     wget -q \
@@ -51,5 +56,4 @@ RUN cd frontend/android && \
     ./gradlew assembleDebug --no-daemon
 
 # ── Export APK ────────────────────────────────────────────────────────────────
-CMD cp frontend/android/app/build/outputs/apk/debug/app-debug.apk \
-       /out/wallet-gen-debug.apk
+CMD ["cp", "frontend/android/app/build/outputs/apk/debug/app-debug.apk", "/out/wallet-gen-debug.apk"]

frontend/capacitor.config.json

@@ -0,0 +1,6 @@
+{
+  "appId": "com.walletgen.app",
+  "appName": "wallet-gen",
+  "webDir": "dist",
+  "bundledWebRuntime": false
+}