Massively Reduce Repo Code with DBOS

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

Folded duplicated web forms, search boxes and org-switch logic into shared pieces: net −116 lines. Clone scans show almost no duplication left (0.22% backend, 0.01% web). Full gate green; PR #4617 merged. Deferred: removing the agent_providers.py twin needs a change to ADR-0009.