Merge branch 'feat/staging-cloud-vite-config'

All staging changes were superseded by evolved implementations on main:
- staging vite config: cloud auto-detection, stagingcloud fallback, and
  /api/users bypass already adopted upstream (dropped X-API-KEY injection)
- hostname-based environment detection: superseded by runtime remoteConfig
- history_v2 array format: superseded by Jobs API
- router auth guard, sentry integrations, ws notifications, remote widget
  auth headers, client_id params: all present in evolved form

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: imick-io