BAGEL: Zero-install browser-based 3D visualizer for ROS bags

BAGEL (BAG ExpLoration) is a fully client-side, open-source web application that lets you inspect, scrub, and visualize ROS 1 and ROS 2 bag files directly in your browser — with zero installation, configuration, or cloud uploads. It supports multiple formats: `.mcap` (Humble/Jazzy), `.db3` (SQLite), and legacy `.bag` files. The 3D panel, built on Three.js, decodes and renders `PointCloud2`, `LaserScan`, `PoseStamped`, `OccupancyGrid`, and `MarkerArray` with proper TF handling, action semantics (ADD, MODIFY, DELETEALL), and lifetime fade-outs. Remote URL streaming via HTTP Range lets you scrub through multi-gigabyte logs in under a second by fetching only the needed chunks. Custom schema injection for `.db3` files uses `@foxglove/rosmsg` validation and local storage, enabling decoding of proprietary message types.

The frontend is built with React 19, TypeScript, and Vite, offloading heavy parsing to Web Workers. It leverages `@mcap/core`, `@foxglove/rosbag`, and `sql.js` (WebAssembly) for in-memory database queries. Compressed ROS1 chunks are handled via `seek-bzip` and `lz4js` in workers, keeping the UI responsive. The time-series panel uses uPlot for instant graphing of any numerical primitive. The author welcomes community feedback on performance, missing primitive types, and UX enhancements. The project is on GitHub and available as a live demo at https://bagel-ros2.vercel.app.