Persist bot mode across restarts via database

Adds a BotSettings key-value table. The active mode is saved
when changed via /bcs-mode and restored on startup.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cogs/commands.py

@@ -559,6 +559,9 @@ class CommandsCog(commands.Cog):
         self.bot.current_mode = mode
         new_config = self.bot.get_mode_config()
 
+        # Persist mode to database
+        asyncio.create_task(self.bot.db.save_setting("current_mode", mode))
+
         # Update bot status to reflect the mode
         status_text = new_config.get("description", "Monitoring vibes...")
         await self.bot.change_presence(