Add form-based PUT update tests via define_form_update_tests macro for all
7 entities. Add hand-written datastar update tests for roasters, roasts,
cafes, brews, and cups. Add brew/cup update API tests (CRUD + auth).
Add put_form, put_form_datastar, create_default_brew, create_default_cup
test helpers.
The PayloadSource::Form branch (redirect response) and form-specific
Submission type parsing were previously untested. Add 19 tests covering
form-encoded POST for all 8 entities, including Datastar+form combo and
edge cases for custom deserializers (TastingNotesInput, optional gear ID,
comma-separated quick notes, date string parsing).
