144 - Surface Relationship Map Decision Maker changes for Tier 0 accounts

Create Salesforce-reportable visibility when the Decision Maker on an Account's Relationship Map changes, focused on Tier 0 renewal-risk accounts—not generic contact edits.

User story

As a regional sales or CS leader for Tier 0 accounts,
I want Decision Maker attribution changes surfaced audibly in Salesforce,
so that we can engage the new buyer before renewals stall.