Connect Atrium to governed Intelligence builds - #154

Outcome

Atrium now submits the reviewed personal Intelligence plan to a governed Core boundary instead of advancing a client-only preview. The host remains domain-neutral and injects the executor that owns domain sources, ontology, watches, and briefing strategy.

Included

• authenticated and currently authorized POST /v1/intelligence/builds/start contract
• exact request identity and authority-use validation
• host-injected domain executor with fail-closed default
• Atrium submission of subject, outcome, source groups, and cadence
• returned Intelligence resource page adopted immediately by the command center
• visible safe-stop behavior when no executor or authority is available

Verification

• focused Core/API/roadmap: 22 passed
• Canvas: 37 files / 307 tests passed
• production Canvas build passed
• Ruff and diff checks passed

Boundary

This PR does not implement a World or Market executor, package Atrium into the wheel, claim live connectors, or publish a release. Those are separate v1 gates.