Work out how to get typesync to run automatically

[josephjclark]

I've just added typesync, which is a super cool package that ensures you have matching @types packages for all your packages.

The only problem is that in pnpm, we have to run it manually.

One day, I'd like to be able to automatically run typesync after pnpm add, pnpm remove and pnpm update (but not pnpm install).

Typesync provides docs to autorun in npm, but this simply doesn't work in pnpm

Options and ideas:

• pnpm does provide some postinstall hooks through a .pnnpmfile.cjs, but a) it'll run on install as well as add, and b) they don't let do you very much. We can't run pnpm commands from these hooks, we can only hack the lockfile
• pnpm has an option to enable npm-style pre/post script hooks. If we enable this, we could probably add postadd, postremove and postupdate scripts. But I think you can only do this on pnpm run, and it has to be passed into the CLI.
• We could use a git hook and run typesync before committing or pushing ,failing if types are not synced. But this is dogmatic and annoying.

[josephjclark]

Be mindful of #756