fix: preserve abuild directory structure in Alpine cleanup

- Replace aggressive rm -rf /home/builduser/packages/ with targeted rm -f of stale .apk files
- Add mkdir -p to ensure abuild output directory exists before build
- Fixes Alpine CI build failure caused by removing required directory structure

.gitea/workflows/ci.yml

@@ -324,7 +324,8 @@ jobs:
       - name: Clean stale Alpine packages
         run: |
           rm -f releases/linux-patch-api-*.apk 2>/dev/null || true
-          rm -rf /home/builduser/packages/ 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