- New VolcengineClient.call_json() for POST+JSON signing (Ark API)
- ArkService for API Key CRUD operations
- Backend views: list/create/toggle/delete ark keys per project
- Frontend: ArkKeysView with project selector, key table, create dialog
- Created key value shown once with copy button
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
