feat(atrium): become the intelligence command center

[eamirian]

What changed

• turns Atrium into a dark, evidence-first command center instead of a generic dashboard
• orients the shell from the governed resource page product_id without hard-coding a domain
• adds coverage, freshness, briefing, attention, and live-change stream hierarchy
• makes Ask ACE a compact sourced-intelligence surface
• enriches resource inspection with optional bounded significance and confidence hints
• adds a generic cross-repository browser gate for domain-owned resource-page artifacts
• records the researched reference lock and explicit design rejections

Why

Atrium is the ACE product experience and shared human control plane. Domain Packs should configure
what Atrium watches; they should not create competing applications. This slice makes that boundary
visible and gives World Intelligence a credible command-center demo without moving World nouns or
data into Core.

Validation

• Canvas unit suite: 297 passed
• production TypeScript/Vite build: passed
• existing Atrium browser journey: passed
• external World domain resource-page browser journey: passed on desktop and mobile
• visual QA completed against the World AI Command Center artifact

Follow-on

The World repository owns the resource-page artifact and demo journey in
World PR #23.
Monitor/subscription and onboarding-agent admission are intentionally follow-on domain work; Core
does not fabricate those records for the demo.