[§9.5] Wire agentplane evidence into Noetica governance-trail panel

[mdheller]

Agentic-Stack §9 action 5. Every Noetica response traceable to a signed agentplane evidence artifact: model routed, policy admitted, memory scope, evidence hash. Builds on #382 (BearBrowser handoff) and #311 (ReasoningRun panel). Part of epic SocioProphet/socioprophet#490.