Paginate Data Management backup inventory and job history

[paullizer]

Summary

• replace fixed Data Management job and backup limits with encrypted, filter-bound created_at/id keyset cursors
• add server-side operation/type, status, scheduled/manual, date-range, and page-size filters while keeping backup summaries global
• add accessible previous/next controls with preserved refresh state and stale-request protection
• deploy the required Cosmos composite index through Bicep/ARM, Terraform, and app maintenance
• add functional, route-contract, security, infrastructure, and authenticated Playwright coverage

Validation

• python -m pytest functional_tests\test_data_management_history_pagination.py functional_tests\test_data_management_security_patterns.py functional_tests\test_cosmos_wave1_app_maintenance.py functional_tests\test_cosmos_wave3a_indexing_maintenance.py ui_tests\test_admin_data_management_settings_ui.py -q (25 passed, 2 skipped; authenticated browser cases require configured base URL/storage state)
• Data Management route policy inventory, unauthenticated contract, and coverage tests (12 passed)
• terraform validate
• az bicep build --file deployers\bicep\main.bicep --outfile deployers\bicep\main.json
• JavaScript/Python syntax checks, XSS sink guardrail, broken-access-control guardrail, and git diff --check

Fixes #1096