Document git-based deployment flow and update scripts

- Add comprehensive deployment architecture documentation to DEPLOYMENT.md
- Include ASCII diagram showing local → Gitea → Unraid flow
- Document all three deployment scripts with examples
- Update scripts to use root@192.168.2.61 for SSH authentication
- Add automatic SSH config setup in deploy.sh for git server port 28
- Include troubleshooting section for common deployment issues

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

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

setup-unraid.sh

@@ -3,7 +3,7 @@
 
 set -e
 
-UNRAID_HOST="${UNRAID_HOST:-192.168.2.61}"
+UNRAID_HOST="${UNRAID_HOST:-root@192.168.2.61}"
 REMOTE_PATH="/mnt/user/docker/custom-dockers/discord-stock-bot"
 
 echo "Setting up Unraid server for git-based deployment..."