Replace syncpack with pnpm catalog

[auscompgeek]

https://pnpm.io/catalogs (new in pnpm v9.5.0)

TODO: does dependabot or renovate bot understand pnpm workspace catalogs?

[pokey]

Nice find; looks neat

The tip in the docs for catalogs looks useful for automatically migrating to catalogs

I wonder if we want to wait until pnpm update supports catalogs (see caveat). Might be a bit annoying otherwise