Load .env file at startup via python-dotenv

Running directly with `python -m gaming_deals_bot` didn't pick up
variables from .env — only the Docker path (--env-file) did. Now
dotenv is loaded before config parsing so both workflows work.

https://claude.ai/code/session_01LPpSZFfyh6vdV5HGFWjoQX

gaming_deals_bot/__main__.py

@@ -6,6 +6,7 @@ import signal
 import sys
 
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
+from dotenv import load_dotenv
 
 from .bot import DealsBot
 from .config import Config
@@ -21,6 +22,7 @@ def setup_logging():
 
 
 async def main():
+    load_dotenv()
     setup_logging()
     logger = logging.getLogger("gaming_deals_bot")