chore(swingset-liveslots): export TypeScript definitions

[sirtimid]

refs: #6343

Description

Properly expose TypeScript definitions from @agoric/swingset-liveslots package by adding TypeScript build steps in package.json which generate the definitions.

Security Considerations

No security impact - only affects TypeScript type definitions which are stripped at compile time.

Scaling Considerations

No scaling impact - changes only affect development-time TypeScript support.

Documentation Considerations

No documentation updates needed - this is a developer-facing change for TypeScript users.

Testing Considerations

Existing type coverage tests continue to pass. No additional testing needed as this only affects type definition exposure.

Upgrade Considerations

No upgrade impact - purely development-time TypeScript support changes.

[mhofman]

I don't understand the motivation for introducing a "types" field in package.json (and the manual ts-types.d.ts file. Our types-index approach should work just as well (if it doesn't, I'd like to understand why)

Adding @turadg as he has practice with similar changes.

[mhofman]

Any reason to change away from our types-index approach? We tend to avoid adding a types field to the package.json as it's often unnecessary if sibling .d.ts files are generated.

Some of this is described in https://github.com/Agoric/agoric-sdk/blob/master/docs/typescript.md

[sirtimid]

One issue is that typescript expects a definition of the index file when we import it, else it can't find the types even with the types-index.js approach. This is solved with the pre/postpack commands. Another issue is that we need to export types that aren't part of the runtime hence the types-index approach, which already handled that.

I was trying to avoid making an exception at the postpack which deletes all the definitions (along with the hardcoded one types-index.d.js) hence the type key. My ts-types.ts is not referenced on runtime somewhere. types-index.js was renamed to ts-types.ts but I can revert that of course. It seemed to me it's not the index since index.d.ts is the index now.

[turadg]

Thanks for explaining. To help keep the codebase manageable we try to be consistent across packages. For this PR please follow the guidelines in https://github.com/Agoric/agoric-sdk/blob/master/docs/typescript.md and if you think they should let's have another PR which updates that guidance and implements the new practice across all the packages.

[sirtimid]

@mhofman @turadg I've reverted the changes with the types field to the package.json and kept the types-index.js approach.

[turadg]

Thanks for the contribution!

[mhofman]

Seems fine with a minor nit.

[turadg]

This failure is real:

> @agoric/[email protected] prepack
> tsc --build tsconfig.build.json

Error: ../vat-data/src/index.js(53,15): error TS2304: Cannot find name 'MapStore'.
lerna ERR! npm run prepack stderr:

It wasn't detected until integration testing that doesn't run on PR pushes by default (until merge or a force:integration tag)

It appears the d.ts broke the ambients. There might be a lot of changes required to get this passing. (Incidentally this is an issue this PR advances so I've linked it in the description.) I can help but probably not until next week.