Separation of dashboard and Donation page frontend

[thaninbew]

Treat dashboard and donation page as separate "apps" within the monorepo. Donation page should remain lightweight to be embedded in wordpress later on, whereas dashboard can be hosted separately.

Both the dono page and the dashboard will need to talk to the backend. by keeping them in one repo:

they can share the same apiClient.ts.
they can share the same types and validation logic from the shared/ folder.

ONLY the dashboard needs auth.

This ticket should split them into apps/dashboard and apps/donation-page, Nx makes that very easy to do, and this is good to do early on.

only work on this ticket if other tickets are merged unless you love love love merge conflicts