fix: remove mkdir -p from Alpine cleanup that broke abuild

- Remove mkdir -p /home/builduser/packages/home/x86_64/ that was creating
  root-owned directories that abuild (running as builduser) couldnt write to
- Keep targeted rm -f of stale .apk files only
- abuild creates its own output directories with correct ownership

.gitea/workflows/ci.yml

@@ -325,7 +325,6 @@ jobs:
         run: |
           rm -f releases/linux-patch-api-*.apk 2>/dev/null || true
           rm -f /home/builduser/packages/home/x86_64/linux-patch-api-*.apk 2>/dev/null || true
-          mkdir -p /home/builduser/packages/home/x86_64/
       - name: Build Alpine package
         run: |
           chmod +x build-alpine.sh