ACME freshness check improvements

.github/workflows/ci.yml

@@ -150,9 +150,22 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6.0.2
 
+      - name: Free disk space (heavy ARM targets)
+        if: contains(matrix.target, 'arm')
+        run: |
+          df -h /mnt /
+          sudo rm -rf /usr/share/dotnet /opt/ghc /usr/local/lib/android /usr/local/.ghcup /usr/local/share/powershell /usr/share/swift /opt/hostedtoolcache/CodeQL
+          sudo docker image prune --all --force || true
+          df -h /mnt /
+
       - name: Add swap (heavy ARM targets)
         if: contains(matrix.target, 'arm')
         run: |
+          mnt_avail=$(df --output=avail -k /mnt | tail -1)
+          if [ "$mnt_avail" -lt 18874368 ]; then
+            echo "Insufficient space on /mnt (${mnt_avail}K available), aborting swap setup"
+            exit 1
+          fi
           sudo fallocate -l 16G /mnt/swapfile
           sudo chmod 600 /mnt/swapfile
           sudo mkswap /mnt/swapfile