cli: add presets option and react preset for typescript

[Trobyss]

Description of Changes

Implements --preset option in spacetime generate cli to provide a way to generate react code under typescript module binding.

Exemple:

spacetime generate --lang typescript --out-dir module_bindings --project-path ./quickstart-chat/server  --preset react

For the moment it's a draft because I'd like to get your feedback first:

• Is this a feature you're interested in?
• How hard is it to keep this up to date?

This is my very first Rust code, so I look forward to your feedback 😇

Implementation Details

• Added a new Preset enum in the CLI to support React preset generation
• Implemented React struct in presets/react/mod.rs that implements the LangPreset trait
• The React preset generates:
  • Context provider and hooks for SpacetimeDB connection
  • Custom hooks for each table in the module
  • Type-safe store hooks using React's useSyncExternalStore
  • Proper TypeScript types and interfaces

Exenple of generated code:

module_bindings/
└── react/
    ├── context.tsx
    ├── index.ts
    ├── useSpacetimeContext.ts
    ├── useSpacetimeXXXStore.tsx (<-- one for each table)
└── index.ts
 ... other generated typescript files

You can find more detailed exemple here: crates/codegen/src/presets/react/doc.md.

For now, there aren't many hooks available, but I'm planning to add some to handle the calls from the reducers in the next few days.

Design issue

Actually, REACT_SPACETIME_CONTEXT_PROVIDER doesn't need to be generated and could be a part of with a react-sdk in spacetimedb-typescript-sdk.

The hooks need to be wrap in a React Context (SpacetimeProvider) to be able to use the useSpacetimeContext hooks and use the connected client (to avoid passing Spacetime client each time in props). I don't know if this is a good thing or a bad thing.

Testing

• Snapshot test
• Manual testing of generated React components

Todo list

• Move REACT_SPACETIME_CONTEXT_PROVIDER to a separate react-sdk package inside spacetimedb-typescript-sdk
• Add reducer call methods/hooks
• Test on larger codebase

Future Improvements

• Add more presets for other frameworks (Vue, Svelte, etc.)
• Improve type safety and error handling in generated hooks

[cloutiertyler]

Ooh this is quite interesting. It might take us a bit to get to this, but we're definitely keen to make our React story better. Not sure if it should be a code gen solution or not. Thanks for raising this!

[Trobyss]

Hey @cloutiertyler!

Glad to hear your comments!
Yes, implementing a feature like this means a lot for future maintenance....
Should I keep implementing React stuff or should I just leave this PR for now?

Anyway, think I'll continue to at least have an 'mvp prod ready', maybe it can give other React developers a good start :)

Trob'