Database stores times in UTC but serialized without timezone info,
causing frontend to misinterpret as local time. Now all datetime
fields include 'Z' suffix to indicate UTC, enabling proper timezone
conversion in the browser.
- Add UTCDatetimeBaseModel base class for Pydantic schemas
- Update model to_dict() methods to append 'Z' suffix
- Affects: tasks, users, sessions, audit logs, translations
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add TranslationLog model to track translation API usage per task
- Integrate Dify API actual price (total_price) into translation stats
- Display translation statistics in admin dashboard with per-task costs
- Remove unused Export and Settings pages to simplify frontend
- Add GET /api/v2/admin/translation-stats endpoint
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
