- SQL generator no longer requires a units col; recode/clone/scale omit units
expressions when none is configured in col_meta
- Source registration validation drops units from required roles (value + date
are the only hard requirements)
- DELETE /api/sources/:id returns 409 when existing versions reference the source
- Setup.jsx surfaces the 409 error via flash instead of silently failing
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>