Adds MultiCollectionController + RerunCollectionController (list/get/create/update/
delete) over the existing MediatR handlers, with response/request DTOs, controller +
contract tests, regenerated OpenAPI + TS types, and thin SPA api-client modules. SPA
editor screens are a follow-up. Rerun request DTO resolves the chosen entity id into
the minimal VM the handler reads (documented inline).
Refs #151, #152
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
timothyandClaude Opus 4.8
a496dad9c9