chore: set up npm workspaces with shared package

[alecananian]

PR Checklist

• Includes changes to desk files
• Describes how you tested the PR locally (test ship vs livenet)
• If a new feature, includes automated tests
• Comments added anywhere logic may be confusing without context

Changes

• Updates repository to use npm workspaces
• Creates shared package at packages/shared with sample shared type to start
• Updates the web UI's group state manager to use the example shared type
• Moves Tlon mobile app into monorepo architecture at apps/tlon-mobile with bundle ID io.tlon.groups.staging

Tested with my livenet ship:

1. Delete all existing node_modules folders in your repo: rm -rf ./**/node_modules
2. Install dependencies at the root level: npm i
3. Follow setup directions in apps/tlon-mobile/README.md
4. Plug in your device or start the iOS simulator and run Tlon mobile: npm run dev:ios

No changes were made to the way the web UI is run for now

[linear]

LAND-1498 Code management: RN + web scaffolding

[alecananian]

Marking as draft because the rest of the CI workflows need updating. But the app package should be good for review.

[mrozanski]

For the new bundle ID, we should use a distinctive app icon so it's. not the same as tlon-mobile's currently in production.
I'll followup in Linear.

[alecananian]

Discussed with @mrozanski and @dnbrwstr, plan now is to move the ./ui folder to ./apps/tlon-web and leave the ./desk folder at the root of the repo since it's not a workspace package. cc @arthyn @Fang- any issues with this folder structure/naming?

[arthyn]

@alecananian sounds good to me

[alecananian]

@mrozanski The web code is now in apps/tlon-web with the PR workflow passing