Banner/queue: reconcile 'K need review' (queue_size) with the dashboard chip count

[gterdem]

Summary

GET /banner/summary defines queue_size as actors with escalation tier ∈ {1,2} (the core ADR-0067 D1(a) gate). The dashboard chip list (deriveTriageActors) can include additional actors above the operator's configurable band/Triage threshold (ADR-0059). So the banner's "K need review" and the number of rendered chips (N) can differ — a user-visible inconsistency ("banner says 2, I see 3 chips").

Acceptance criteria

• Decide the single authoritative definition of "needs review" (tier ∈ {1,2} vs tier ∈ {1,2} OR band ≥ triage threshold) and make BOTH the banner K and the chip list derive from it — one source of truth, no third number.
• If the band-threshold actors count, the backend queue_size must read RuntimeConfig's triage threshold (not a second client-side comparator); if they don't, the chip list must exclude them. Pick one; document why.
• Golden byte-identical; a test pins K == rendered chip count.

Origin: #55 (PR #99/#101) flag. Related: ADR-0059, ADR-0067 D1(a).