Refactor API POSTs and trpc mutations to use Astro actions

[lukeshafer]

https://docs.astro.build/en/guides/actions/

Astro recently added this API to create type-safe actions that are also SSR/no-js friendly. Look into our current API and see where this can replace existing endpoints

Stuff to replace

• Anything to do with trades
• The open-packs page
• A bunch of stuff on the admin site

Questions:

• How will this work with auth?
  • probably the same way we handle auth in Astro rn, i.e. check the session type and redirect if needed
  • Can probably make a generic function to handle auth stuff

Strategies:

Organize actions in the src/actions directory in files based on the domain. E.G.

• actions/users.ts
• actions/designs.ts
• actions/trades.ts
• actions/open-packs.ts

Concerns:

• Are we sharing endpoints between main and admin sites? If so, moving to actions would cause some duplication
  • counterpoint: if there are shared endpoints, they may have slightly different requirements that we can account for in the action instead of one generic endpoint