Faster Android builds: ccache, Gradle build cache, 64-bit only, no release lint

Most of a build was compiling the same C++ twice per APK with nothing reused between builds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011Y2iUsKEWDuRGjK5FPmcUP

deploy/android-builder/Dockerfile

@@ -5,11 +5,11 @@
 #
 # Versions match what React Native 0.86 / Expo 57 ask for
 # (node_modules/react-native/gradle/libs.versions.toml). Gradle downloads anything
-# else it needs on first use; the workflow keeps ~/.gradle in a volume.
+# else it needs on first use; the workflow keeps ~/.gradle (and ccache's ~/.ccache) in volumes.
 FROM node:22-bookworm
 
 RUN apt-get update \
- && apt-get install -y --no-install-recommends openjdk-17-jdk-headless unzip \
+ && apt-get install -y --no-install-recommends openjdk-17-jdk-headless unzip ccache \
  && rm -rf /var/lib/apt/lists/*
 
 ENV JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64 \

deploy/gitea-runner/config.yaml

@@ -20,7 +20,8 @@ container:
   # Use Docker's default network instead of creating one per job: a server with many compose
   # projects runs out of address pools ("all predefined address pools have been fully subnetted").
   network: bridge
-  # The volumes the workflow may mount (Gradle and npm caches), and nothing else.
+  # The volumes the workflow may mount (Gradle, npm and ccache caches), and nothing else.
   valid_volumes:
     - musicshare-gradle
     - musicshare-npm
+    - musicshare-ccache