add QoL tooling for ad hoc work with JSON, e.g. jq

[charlesfrye]

this is weirdly hard -- JSON doesn't show up nicely in VS Code Jupyter; JSON in the terminal has been a PITA with shell-specific nonsense

[charlesfrye]

ways to solve this:

• figure out a way to make JSON display look good in VSCode, e.g. by installing an extension, and demonstrate it works in the devcontainer too
• run jq on data from Python without writing to disk in a way that's robust to shell choice

[charlesfrye]

Might be overkill, but mercury can give a nice "JSON-in-Jupyter" experience. Need to test in VS Code and in Colab.