Proofread default language translations and fix plural keys via AI

Publishes a proofread task to the queue. The consumer reads all source_story entries for the given projectType + story in the default language, sends them to AI for proofreading and plural key fixing, then updates changed records.

curl -X POST "https://example.com/api/v2/default-translations/proofread-default" \  -H "Content-Type: application/json" \  -d '{    "projectTypeId": 8,    "storyId": 1  }'

{  "message": "Proofread task accepted"}