Standardize types

[2blo]

Use as few downstream types as possinle prefer Post["x"] or central zod schema.

• [ ] dont cast dynamic routes to strings
• [ ] always pass entire posts objects, to avoid complexity?
• [ ] dont duplicate schemas
• [ ] dont break apart schemas for objects:

  {
  before: Post["before"].
  after: Post["after"],
  ...,
  }

  -->

  {
  before
  after
  ...,
  } : Post 

  ?

• [ ] ...