Merge organizations or people — non-destructive, effective dedupe (likely its own microfrontend)

[mpstaton]

Context:

• Merge-Organizations-Or-People-Non-Destructive-Dedupe.md

When two rows are the same real-world entity: absorb (slug → aliases, arrays union'd, edges re-pointed, observations preserved), never delete; operator picks the survivor field-by-field. Canonical layer only — opportunities stay never-merged by design.