Multi-touch attribution

Each opportunity attributes contributors across role, pool, and evidence. Splits must total exactly 100% per pool by default.

Demo — no real records modified

Opportunity	Customer	Source	Contributors	Pools	Status

Splits must total exactly 100% per single pool by default.
Multiple separate pools may each total 100%.
Over-allocation within one pool is invalid.
Stacked plan families may coexist across separate pools.
Leadership override requires a separate pool or documented exception.
Missing attribution, duplicate participants, and preexisting-pipeline conflicts must be flagged.