fix: complete production QA flows

[Krisor1986]

Problem

Production QA exposed blocked workflows and unreadable states across clients, jobs, authentication, AI, invitations, settings, and dark mode.

Changes

• add client next-action creation and keep client modal actions visible
• add job status updates and tenant-scoped stage creation
• apply the company brand colour and repair dark-mode contrast
• provide safe, reviewable AI clarification drafts during private-service outages
• support Resend password-reset delivery and secure manual member invitations
• localize operational errors and handle HTML or non-JSON API responses cleanly
• align AI-agent document fields and harden account and data loading across screens

Validation

• backend: 207 passed, 2 skipped
• frontend: 26 passed
• ESLint passed
• Vite production build passed
• browser smoke tests passed for client, next action, job, status, stage, invitation, brand colour, and dark dashboard flows

Deployment note

Configure RESEND_API_KEY and AUTH_EMAIL_FROM on Render before enabling production password-reset email delivery.