Improve Operator Console Empty States

[chendbox]

Summary

Improve copy and guidance in the React operator console when there are no jobs yet, no token connected, or no recent worker activity.

Why This Matters

The operator console is part of the first-run experience. Better empty states make the demo easier to understand and reduce confusion for first-time users.

Scope

Examples of useful improvements:

• clarify what users can see without an operator token
• explain what to do when there are no jobs yet
• improve guidance when workers are not active yet
• make the first-run path easier to understand

Acceptance Criteria

• empty or low-data states feel intentional and informative
• copy is concise and action-oriented
• changes match the current visual style of the console

Good Starting Points

• src/app/ui-react/src/
• src/app/api/routes/ui.py
• README.md