schema: Generate Go and Typescript from Thema coremodels (#49193)

* Add go code generator for coremodels

* Just generate the entire coremodel for now

Maybe we'll need more flexibility as more coremodels are added, but for
now this is fine.

* Add note on type comment about stability, grodkit

* Remove local replace directive for thema

* Generate typescript from coremodel

* Update pkg/coremodel/dashboard/addenda.go

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

* Update cuetsy to new release

* Update thema to latest

* Fix enum generation for FieldColorModeId

* Put main generated object at the end of the file

* Tweaks to generated Go output

* Retweak back to var

* Add generated coremodel test

* Remove local replace statement again

* Add Make target and call into cuetsy cmd from gen

* Rename and comment linsrc for readability

* Move key codegen bits into reusable package

* Move body of cuetsifier into codegen pkg

Also genericize the diffing output into reusable WriteDiffer.

* Refactor coremodel generator to use WriteDiffer

* Add gen-cue step to CI

* Whip all the codegen automation into shape

* Add simplistic coremodel canonicality controls

* Remove erroneously committed test

* Bump thema version

* Remove dead code

* Improve wording of non-canonicality comment

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

public/app/plugins/igen.go

@@ -0,0 +1,3 @@
+package plugins
+
+//go:generate go run gen.go