Reenable Specta integration

[oscartbeaumont]

This fixes the commented out Specta integration resolving the TODO comment.

It might be worth moving the type exporting code into the startup of the application if possible when doing a debug build so that you don't need to run cargo test ... to generate the bindings but I don't know enough about Graphite's setup to know where is best. I also suppose any Rust running in wasm would not be a good place for that as it won't have filesystem access so a better place may not exist.

TODO:

• Decide on approach
• Fix the errors with linter (we can do that from the Specta side)

[Keavon]

Thank you for writing the library and helping us restore this! I'm eager to do the refactor which replaces messages.ts with these generated bindings.