Docs · Reconcile chi.md (HumanInteractionEvent already collapsed into EmissionEvent)

[wow-miley]

Context. Recon #543 found docs/concepts/chi.md (last_verified 2026-06-04) is behind the code: it describes HumanInteractionEvent as one of four uncoordinated CHI paths awaiting collapse into Emission, but in merged code (#508, db0329a) that collapse already happened — HumanInteractionEvent is now a sealed interface … : EmissionEvent (InputRequested : EmissionEvent.Produced, InputProvided : EmissionEvent.Resolved). Leaving this stale will mislead downstream authors (it already nearly misled the motor epic).

Objective. Reconcile chi.md with reality.

Changes (AMPERE repo, docs only)

• Update docs/concepts/chi.md: HumanInteractionEvent is already an EmissionEvent specialization (cite Emission protocol foundation — domain types, EmissionEvent family, Confidence enum (Wave 0) #508). The remaining separate CHI paths are three: ToolAskHuman, MessageEvent.EscalationRequested, AgentPause — not four.
• Refresh last_verified / add the Concept-Verified: trailer per the concept-cell convention.
• If tracked_sources lists HumanInteractionEvent.kt, confirm it's accurate.

Validation

scripts/validate-concepts.sh passes with no staleness warning for chi.md; a reviewer confirms the "three remaining paths" framing matches EmissionEvent.kt / HumanInteractionEvent.kt.

Out of scope

Any code change; collapsing the three remaining CHI paths (that's separate, larger work).

Scope ~1 pt · Model: Haiku (or Sonnet low) — docs only.