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

.gitea/workflows/android.yml

@@ -22,8 +22,8 @@ jobs:
     runs-on: musicshare-android
     container:
       image: musicshare-android-builder
-      # Keep Gradle and npm downloads between builds.
-      options: -v musicshare-gradle:/root/.gradle -v musicshare-npm:/root/.npm
+      # Keep Gradle (downloads and build cache), npm, and compiled C++ (ccache) between builds.
+      options: -v musicshare-gradle:/root/.gradle -v musicshare-npm:/root/.npm -v musicshare-ccache:/root/.ccache
     timeout-minutes: 150
     env:
       SERVER: ${{ github.server_url }}