Initial commit: Brother QL USB-to-Network Bridge

- TCP server exposing USB Brother QL printers on port 9100
- Supports all Brother QL series label printers
- Async architecture for handling concurrent print jobs
- Raspberry Pi deployment script and systemd service
- Documentation for setup and InvenTree integration

.gitignore

@@ -0,0 +1,20 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+.venv/
+venv/
+*.egg-info/
+
+# uv
+uv.lock
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db