feat: add one-click deploy script + project optimization

- deploy.sh: one-click deployment (venv + pip deps + .env + gunicorn + systemd + firewall)
- gunicorn_config.py: unified gunicorn config with env var overrides
- .env.example: full env var template (admin, security, port, session, backup, etc.)
- app.py: optional dotenv .env file loading
- requirements.txt: add python-dotenv

app.py

@@ -5,6 +5,16 @@ import logging
 import threading
 import time
 from flask import Flask
+
+# 可选: 加载 .env 文件（生产部署推荐用 systemd EnvironmentFile）
+try:
+    from dotenv import load_dotenv
+    _env_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), ".env")
+    if os.path.isfile(_env_path):
+        load_dotenv(_env_path)
+except ImportError:
+    pass
+
 from config import Config
 from database import db
 from models import Instance  # 触发表创建