Action Items Compress — Consolidate vault tasks into a single ranked backlog

Scans the entire vault for action items, deduplicates them, scores each by priority (PersonWeight × 100 + Committed × 80 + ...), writes one consolidated `Action Items.md` at vault root, and demotes all source tasks to breadcrumbs. Asks before writing. Triggers: "compress action items", "consolidate my tasks", "/action-items compress".