ci: free disk space before build to avoid runner out-of-space

Gradle + NDK + node_modules exhaust the 14 GB on ubuntu-latest runners.
Remove .NET, Haskell, Chromium, Swift, PowerShell preinstalled tools (~6 GB).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/build-android.yml

@@ -15,6 +15,15 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Free disk space
+        run: |
+          sudo rm -rf /usr/share/dotnet /usr/local/share/boost /opt/ghc
+          sudo rm -rf /usr/local/share/chromium /usr/local/share/powershell
+          sudo rm -rf /usr/share/swift /usr/local/julia*
+          sudo apt-get autoremove -y > /dev/null 2>&1
+          sudo apt-get clean
+          df -h
+
       - uses: actions/checkout@v4
 
       - uses: actions/setup-node@v4