feat: add Discord bot integration

- Discord bot runs in background thread alongside desktop app
- State synchronization between Discord and desktop waifu
- Commands: !hello, !status
- Responds to mentions and DMs
- Complete setup guide in DISCORD_SETUP.md
- Graceful fallback if no token configured

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

README.md

@@ -56,15 +56,14 @@ cp .env.example .env
 
 ### Discord Setup (Optional)
 
-1. Create a Discord bot at https://discord.com/developers/applications
-2. Enable these intents:
-   - Message Content Intent
-   - Server Members Intent
+**See [DISCORD_SETUP.md](DISCORD_SETUP.md) for detailed instructions.**
+
+Quick setup:
+1. Create bot at https://discord.com/developers/applications
+2. Enable "Message Content Intent" in Bot settings
 3. Copy bot token to `DISCORD_BOT_TOKEN` in `.env`
-4. Invite bot to your server with permissions:
-   - Send Messages
-   - Read Message History
-   - Use Slash Commands
+4. Invite bot to your server using OAuth2 URL generator
+5. Bot will automatically start with the desktop app!
 
 ### LLM Setup (Optional)