Sprint 6B: governed request submission and approval workflow UI

[samrusani]

Summary

• wire the web shell to the shipped governed request, approval, and task seams
• add approve and reject actions, task summary/detail views, and route-level loading states
• keep the sprint inside the existing backend surface with explicit fixture fallback where live config is absent

Verification

• npm run test in apps/web: PASS
• npm run build in apps/web: PASS

Notes

• npm run lint is still not a stable non-interactive check
• next build still causes local tsconfig and next-env churn unless reverted