chore: add python-dotenv for .env loading

pyproject.toml

@@ -5,6 +5,7 @@ description = "Multi-AI collaborative brainstorming platform"
 requires-python = ">=3.11"
 dependencies = [
     "python-telegram-bot",
+    "python-dotenv",
     "sqlalchemy",
     "httpx",
     "aiosqlite",

src/moai/bot/main.py

@@ -8,6 +8,7 @@ Usage:
 
 import logging
 
+from dotenv import load_dotenv
 from telegram.ext import Application, ApplicationBuilder
 
 from moai.bot.config import BotConfig
@@ -53,6 +54,7 @@ def main() -> None:
     """
     global _config
 
+    load_dotenv()  # Load .env file
     _config = BotConfig.from_env()
 
     logging.basicConfig(