docs: install deps via requirements.txt

README.md

@@ -40,7 +40,7 @@ cd SubMind
 python -m venv .venv
 source .venv/bin/activate  # Windows: .venv\Scripts\activate
 pip install -U pip
-pip install python-telegram-bot pandas matplotlib python-dateutil dateparser python-dotenv requests
+pip install -r requirements.txt
 ```
 
 ### 3) 配置环境变量