Reduce Codebase via Refactoring, DBOS Migration

Identify an opportunity to massively reduce the amount of code (lines of code) in any part of the repo: - Similar functionality that can be unified and reused - Code that has been valuable but no more - Front end component or group of them duplicates another component functionality. Use the most modern and nice looking - Move to DBOS and get rid of supporting functionality relying on DBOS - etc. Implement it

Single-homed credential, user and usage form pieces; TenantsPanel on DataTable (net −46; big cuts were taken by earlier runs). PR #4918 merged, CI + Jaah Deploy green; local smoke has 5 pre-existing failures. UI follow-ups in report (no creation licence).