D4: Service entry convention — def self.call(...) = new(...).call

[bstruong]

Files: `app/services/normalizer.rb` (`#normalize!`), `app/services/ingester.rb` (`#ingest!`), `app/services/feed_profile_validator.rb` (`#validate!`)

SABER convention: services have a single public method `#call`, with `def self.call(...) = new(...).call` shortcut.

CASTER is mixed — queries already use `.call`, but services use entry-method names like `#normalize!`/`#ingest!`/`#validate!`.

Action: rename entry methods to `#call`. Add the `.call` class-method shortcut. Update rake task call sites.

Cosmetic but makes the codebase scannable.