Build a browser-based WebSerial setup and update utility

[PurpleSentinel]

Parent: #23

Summary

Provide a simple host interface for configuration, diagnostics, data export, and guided firmware installation without requiring Python tools.

Acceptance criteria

• Detect compatible devices and show firmware and hardware versions.
• Edit validated settings using the versioned USB protocol.
• Download exported data and display diagnostics.
• Guide updates with clear recovery instructions and no silent data loss.
• Document supported browsers and test disconnect and reconnect behavior.

Roadmap group

Data, configuration, and maintenance