Add JSON schema

[rohanmahy]

What I did

I added a Claude-generated JSON Schema with some hand-tweaks. Addresses Issue #24

Did it work?

Mostly.

• I hand checked and edited the schema for the objects I am familiar with. I did not verify redacted, appended, and analysis objects against the text.
• I did not delve deeply into the logic to make sure exactly the correct fields are present for a transfer
• None of the examples validated originally, but the issues I found were confined to the following:
  • vcon has to be "0.0.2"
  • uuid, created_at, and parties are required
  • group (even if empty) is prohibited if you also have redacted or appended
  • body is supposed to be a string, not an object, so you need to redo your tooling to escape all the quotes, etc. This is probably going to suck.

How do I check if something validates?

Install a validator. For example this popular python one worked well:

brew install check-jsonschema

check-jsonschema --schemafile vcon-schema.json examples/ab.vcon

What's next

• Refactor the body+encoding or url+content_hash parameters and restrictions to be common.
• Add extension points
• Make sure that all the examples have the mandatory vcon version; and the uuid, created_at, and parties mandatory fields.
• Make sure that the examples don't have more than one of redacted, appended, or group.
• Fix the examples with bodies so they are strings instead of vcon objects
• Fix the tooling so it can pretty print bodies with escaped json bodies
• Hand check any logic errors in dialog
• Hand check everything in analysis, redacted, appended
• Profit!