80 - Add Account Plan timeline with filterable plan history

Add an Account Plan timeline in CRUSH with a chronological view of meaningful plan changes—similar to a Salesforce History / Field History experience—with filters for activities, objectives, opportunities, and other categories (exact mix TBD with PM).

User story

As an AE or strategist working an Account Plan in CRUSH,

I want a filterable timeline of plan-related updates (not just a flat history list),

so that I can orient quickly, tell the story of plan motion, and drill into what changed without bouncing across unrelated tabs.