fix: use runner home dir for work dir

.gitea/workflows/build.yml

@@ -17,9 +17,10 @@ jobs:
 
       - name: Generate demo content + Dockerfile
         run: |
-          cd /workspace
-          [ -d demo-frontend ] || git clone http://joe:${GITEA_TOKEN}@192.168.1.212:3000/joe/demo-frontend.git
-          cd demo-frontend
+          WORK=/root/.cache/demo-frontend
+          mkdir -p $WORK
+          cd $WORK
+          [ -d .git ] || git clone http://joe:${GITEA_TOKEN}@192.168.1.212:3000/joe/demo-frontend.git .
           git pull
 
           cat > package.json <<'EOF'
@@ -41,13 +42,13 @@ jobs:
 
       - name: Build frontend
         run: |
-          cd /workspace/demo-frontend
+          cd /root/.cache/demo-frontend
           npm install --silent
           npm run build
 
       - name: Docker build & push
         run: |
-          cd /workspace/demo-frontend
+          cd /root/.cache/demo-frontend
           SHORT=${GITHUB_SHA::8}
           TAG="${REGISTRY}/demo-frontend:${SHORT}"
           LATEST="${REGISTRY}/demo-frontend:latest"