Refresh Backup, Migrate & Restore admin workflow

[paullizer]

Summary

Refresh the Admin Settings data-management tab into a clearer Backup, Migrate & Restore control center.

Scope

• Reorganize the tab around backup, migration, restore readiness, operations history, and advanced repair.
• Replace technical migration terminology with admin-friendly labels.
• Add setup/configuration guidance modals.
• Separate RU Boost permission validation from Cosmos data-copy access validation.
• Add a staged restore workflow that reviews backup readiness and blocks execution when backend restore application support is unavailable.

Validation

• Focused Data Management, UI, and route tests should cover the updated workflow.
• JavaScript and Python syntax checks should pass.
• Whitespace diff checks should pass.