Add missing filters, orderings and columns to the super-admin Users page

Page: /admin/users (Users + Credentials tabs). Source: audit report-users.md.

**Users tab** (adminUsersV2, all <=26.4.0 unless noted):

- Filters: createdAt (datetime), domainName, integrationName, domain.isActive, project.isActive.
- role filter: add ADMIN and MONITOR options (UserRoleV2 has 4 values, UI offers 2).
- PROJECT_NAME ordering + a Projects column (hidden by default) listing project names.
- CSV export must forward the property filter, not only the status radio.

**Credentials tab** (keypair_list graphene, all <=26.4.0):

- Bug: Access Key column sorter emits `accessKey` (no sortKey) and the server rejects it -> add `sortKey: access_key`.
- Filters: full_name, created_at, last_used, rate_limit, num_queries, projects.
- Columns: last_used (sortable), full_name (sortable).

Verify every filter/order live against the test manager.

JIRA Issue: FR-3908

Start with the /admin/users page and the audit report-users.md, then trace the adminUsersV2 Users tab and keypair_list graphene Credentials tab. Verify each listed filter, ordering, column, and CSV property filter against the test manager; done means the server accepts the sort key and every requested control works live.

Written by the indexing model from the issue text.