Fix typescript problems

[jacobtylerwalls]

Fix typescript problems exposed after latest pushes to dev/7.6.x

Closes #21

Take this opportunity to simplify types and not mix string | number for new items versus existing items; just check instead whether something looks like a UUID to tell if it exists on the server.

[jacobtylerwalls]

@chrabyrd Would you happen to know why vitest is failing here? It's passing on arches-lingo but only because the dummy test declarations is not found there (it's under src/). Here it's failing harder (the file is under src/arches_references).

[chrabyrd]

@chrabyrd Would you happen to know why vitest is failing here? It's passing on arches-lingo but only because the dummy test declarations is not found there (it's under src/). Here it's failing harder (the file is under src/arches_references).

Yes. declarations.d.ts hasn't been updated, it still has

import("../../node_modules/arches/arches/app/src/declarations.d.ts");

[chrabyrd]

lgtm