Runs the Lemon doctor check suite and builds the aggregate diagnostic report used by CLI and support tooling.

Registering checks

The built-in checks cover what lemon_core itself owns (config, secrets, runtime, providers, and the proof artifacts other apps write). Apps that own their own domain register additional check modules, which run after the built-ins:

config :lemon_core, :doctor_checks, [MyApp.Doctor.Checks.Widgets]

A check module only has to export run/1 returning a list of LemonCore.Doctor.Check structs. Modules that cannot be loaded are skipped, so a registration left behind by a removed dependency is not fatal.