refactor(php): inject IL10N into services, translate exception messages at throw site

[vitormattos]

Problem

t() was being called with $exception->getMessage() in controller catch blocks:

return new DataResponse(['message' => $this->l10n->t($exception->getMessage())], Http::STATUS_BAD_REQUEST);

This is incorrect because translation extraction tools scan source code for t('literal string') patterns — they cannot discover dynamic strings.

Solution

• Inject IL10N into FieldDefinitionService and FieldValueService
• Call t('literal string') at the throw site inside the services, so exceptions already carry translated messages
• Controllers use $exception->getMessage() directly in catch blocks (no t() wrapping)

Dynamic fragments (e.g. option name, JSON error) go into the second parameter array as intended by the l10n API.