ci: prune dangling images after successful deploy

Removes <none>-tagged images left over from previous builds.
Only affects untagged images (dangling=true) — never touches other
projects' named images (soroushasadi-site, drsousan, etc.).
Also logs disk usage after prune.

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

.gitea/workflows/ci-cd.yml

@@ -431,4 +431,12 @@ jobs:
           echo "=== meezi-redis network state ==="
           docker inspect meezi-redis --format='{{json .NetworkSettings.Networks}}' 2>&1 || true
 
-      # Intentionally no image pruning — disk cleanup is done manually on the server.
+      - name: Prune dangling images
+        if: success()
+        run: |
+          # Remove untagged (<none>) images left over from this and previous builds.
+          # --filter dangling=true only removes images with no tags; never touches
+          # other projects' named images (soroushasadi-site, drsousan, etc.).
+          docker image prune -f
+          echo "Disk after prune:"
+          df -h /