ci: add GitHub action to clean up runner disk space

Define a composite action to remove large toolsets, unused packages,
Docker images, and caches from the GitHub runner, freeing up disk space
for builds.

Author: ffranr

.github/actions/cleanup-space/action.yaml

@@ -0,0 +1,50 @@
+name: "Clean up runner disk space"
+description: "Removes large, non-essential toolsets to free up disk space on the runner."
+
+runs:
+  using: "composite"
+  steps:
+    - name: Free up disk space
+      shell: bash
+      run: |
+        echo "Removing large toolsets to free up disk space..."
+        echo "Disk space before cleanup:"
+        df -h
+
+        # Remove dotnet to save disk space.
+        sudo rm -rf /usr/share/dotnet
+        # Remove android to save disk space.
+        sudo rm -rf /usr/local/lib/android
+        # Remove ghc to save disk space.
+        sudo rm -rf /opt/ghc
+        # Remove large packages.
+        sudo rm -rf /usr/share/swift
+        sudo rm -rf /usr/local/julia*
+        sudo rm -rf /opt/hostedtoolcache
+
+        # Remove docker images to save space.
+        docker image prune -a -f || true
+
+        # Remove large apt packages.
+        sudo apt-get remove -y \
+            '^aspnetcore-.*' \
+            '^dotnet-.*' \
+            '^llvm-.*' \
+            'php.*' \
+            '^mongodb-.*' \
+            '^mysql-.*' \
+            azure-cli \
+            google-chrome-stable \
+            firefox \
+            powershell \
+            mono-devel \
+            libgl1-mesa-dri 2>/dev/null || true
+        sudo apt-get autoremove -y
+        sudo apt-get clean
+
+        # Remove caches.
+        sudo rm -rf /usr/local/share/boost
+        sudo rm -rf "$AGENT_TOOLSDIRECTORY"
+
+        echo "Disk space after cleanup:"
+        df -h