Refresh Backup, Migrate & Restore admin workflow

[paullizer]

Summary

• Reworks Admin Settings Data Management into a clearer Backup, Migrate & Restore workflow with start-here guidance and configuration modals.
• Replaces technical migration wording with admin-friendly labels and updates the destructive migration confirmation phrase.
• Separates destination Cosmos RU Boost permission testing from Cosmos data-copy access validation.
• Integrates with the restored Backup Inventory restore workflow from Development, including restore policy/surface review, preflight, and queueing for supported restore jobs.
• Updates Data Management docs, release notes, and app version to 0.250.108 after resolving Development conflicts.

Validation

• python -m pytest functional_tests\test_data_management_destination_cosmos_capacity.py functional_tests\test_data_management_restore_workflow.py functional_tests\test_data_management_incremental_migration_modes.py functional_tests\test_data_management_security_patterns.py ui_tests\test_admin_data_management_settings_ui.py functional_tests\route_tests\test_route_blueprint_policy_inventory.py functional_tests\route_tests\test_route_unauthenticated_policy_contract.py functional_tests\route_tests\test_route_policy_test_coverage.py
• node --check application\single_app\static\js\admin\admin_data_management.js
• python -m py_compile application\single_app\functions_data_management.py application\single_app\route_backend_data_management.py application\single_app\functions_data_management_restore_state.py functional_tests\test_data_management_destination_cosmos_capacity.py functional_tests\test_data_management_restore_workflow.py functional_tests\test_data_management_incremental_migration_modes.py functional_tests\test_data_management_security_patterns.py ui_tests\test_admin_data_management_settings_ui.py
• git -c core.whitespace=blank-at-eol,blank-at-eof,space-before-tab,cr-at-eol diff --check

Fixes #1140