Update project setup scripts and enhance README for clarity

- Modified the backend setup script to clear the virtual environment before installation.
- Improved README.md by restructuring the prerequisites section into a table for better readability.
- Added installation instructions for the `uv` package and clarified terminal requirements post-installation.

package.json

@@ -4,7 +4,7 @@
   "description": "MiroFish - 简洁通用的群体智能引擎，预测万物",
   "scripts": {
     "setup": "npm install && cd frontend && npm install",
-    "setup:backend": "cd backend && uv venv && uv pip install -r requirements.txt",
+    "setup:backend": "cd backend && uv venv --clear && uv pip install -r requirements.txt",
     "setup:all": "npm run setup && npm run setup:backend",
     "dev": "concurrently -n \"backend,frontend\" -c \"yellow,cyan\" \"npm run backend\" \"npm run frontend\"",
     "backend": "cd backend && uv run python run.py",