Support Automatic browser debugging

*Automatic browser debugging* opens a debug sessions for URLs clicked from the terminal. If users really use it it would add a happy path that avoids extra configuration.

https://github.com/microsoft/vscode-js-debug#automatic-browser-debugging

Start by reading the linked VS Code JS Debug automatic browser debugging documentation, then inspect this repository's debugger entry points to determine how that workflow could integrate with Firefox. Done should mean that URLs clicked from the terminal can open a Firefox debug session without extra configuration, with the expected behavior verified by repository tests.

Written by the indexing model from the issue text.