Create api/mod.rs with API router and webauthn router construction.
Create app/mod.rs with page router and static asset handlers. Rewrite
routes/mod.rs to combine api::router() + app::router(). Widen
support.rs load_*_options visibility to pub(in crate::application::routes).
Split each mixed file along the api/page boundary:
- account.rs: page handler + view types to app/, API handlers to api/
- checkin.rs: checkin_page to app/, submit_checkin to api/
- webauthn.rs: register_page + cli_callback_page to app/
Move home, auth, data, add, and timeline page handlers to routes/app/.
Update import paths: super::is_authenticated to
crate::application::routes::is_authenticated, super::entity:: to
crate::application::routes::api::entity:: in data.rs and add.rs.
