Optimize CI by using a custom Docker container with pre-installed dependencies.

This change introduces a Docker container (`.ci/container/Dockerfile`) that pre-installs:
- OpenJDK 8 (ZuluFX), 11, 17, 21, and 25 (Zulu).
- Android SDK (command-line tools, platform-tools, build-tools) and NDK dependencies.
- Ant, Maven, Python 3.
- Codename One binaries (`cn1-binaries`).
- Required libraries for headless UI testing (xvfb, libgl1-mesa-dri, libncurses6).

Updates `pr.yml`, `ant.yml`, and `scripts-android.yml` to run jobs inside this container (`ghcr.io/codenameone/codenameone/ci-container:latest`), removing redundant setup steps (JDK download, tool installation) to improve build speed and reproducibility.

The workflow `.github/workflows/build-container.yml` is added to build and push this container image to GHCR, ensuring the image tag is always lowercase to comply with registry requirements.

Also updates `scripts/setup-workspace.sh` to respect the `CN1_BINARIES` environment variable and handle the pre-configured environment correctly.

Author: google-labs-jules[bot]

.ci/container/Dockerfile

@@ -19,7 +19,7 @@ RUN apt-get update && apt-get install -y \
     libxxf86vm1 \
     ant \
     maven \
-    libncurses5 \
+    libncurses6 \
     libstdc++6 \
     && rm -rf /var/lib/apt/lists/*
 

.github/workflows/pr.yml

@@ -203,6 +203,9 @@ jobs:
         script: |
           const { publishQualityComment } = require('./.github/scripts/publish-quality-comment.js');
           await publishQualityComment({ github, context, core });
+    - name: Link cn1-binaries
+      run: |
+        ln -sf $CN1_BINARIES ../cn1-binaries
     - name: Build with Ant
       run: xvfb-run ant test-javase
     - name: Build CLDC11 JAR

.github/workflows/scripts-android.yml

@@ -98,13 +98,6 @@ jobs:
       GH_TOKEN: ${{ secrets.CN1SS_GH_TOKEN }}
     steps:
       - uses: actions/checkout@v4
-      - name: Free Disk Space
-        if: matrix.id != 'default'
-        run: |
-          rm -rf /usr/share/dotnet
-          rm -rf /usr/local/lib/android/sdk/ndk
-          rm -rf /opt/ghc
-          rm -rf /usr/share/swift
       - name: Set JDK_HOME
         if: matrix.id != 'default'
         run: echo "JDK_HOME=/usr/lib/jvm/zulu-${{ matrix.java_version }}-amd64" >> $GITHUB_ENV