fix: delete docker build cache in integration test

.github/workflows/integration-test.yml

@@ -35,6 +35,10 @@ jobs:
           done
           echo "Service is up!"
 
+      - name: Delete Docker build cache
+        run: |
+          docker builder prune --all --force
+
       - name: Preload Ollama model
         run: |
           docker exec ollama ollama pull qwen:0.5b-chat-v1.5-q2_K