Model reputation as counterparty assurance gradient across four tiers

Add research on the journey from gamable opinion signals (reviews, ratings)
through observed metrics (PAYDEX, SLA stats), financial commitments (bonds,
escrow), and adjudicated outcomes (arbitration, courts). Resolve OpenQuestions:
no Reputation entity; use Reputation Signal, Performance Evidence, Commercial
Commitment, and Adjudication Outcome with Counterparty Assurance Gradient pattern.

model/ConceptualModel.md

@@ -226,6 +226,29 @@ Identity representations vary in persistence based on commercial stake:
 Commercial binding does not merge layers. It increases assurance requirements and
 lifecycle rigor on the records and relationships already in the model.
 
+## Counterparty Assurance Gradient
+
+Counterparty reliance escalates through four evidence tiers. Model each tier
+explicitly; do not collapse into a single "reputation score."
+
+| Tier | Assurance | Typical evidence | Canon elements |
+| --- | --- | --- | --- |
+| 1 — Opinion | Weak; gamable | Star ratings, reviews, karma | Reputation Signal (Evidence Source) |
+| 2 — Observed | Evidence-based | PAYDEX, SLA metrics, KYC outcome | Performance Evidence (Evidence Source) |
+| 3 — Committed | Financial / contractual | Bond, escrow, signed SLA, mandate | Commercial Commitment + Evidence |
+| 4 — Adjudicated | Legal / binding dispute | Arbitration, judgment, enforcement | Adjudication Outcome (Evidence Source) |
+
+**Trust Relationship** should cite `assurance_basis` (tier + evidence references).
+Escalation path: dispute on committed terms → automated platform resolution →
+contractual ADR → courts. De-escalation via supersession lifecycle, not silent delete.
+
+**Attribution rule:** opinion may bind to Persona/Profile in a platform Scope;
+observed and committed tiers prefer Commercial Record + Registry Identifier;
+adjudicated tiers require Legal Entity / Organization actors.
+
+No standalone Reputation entity — aggregate downstream if needed; preserve tier
+provenance in canon.
+
 ## Scenario Gaps
 
 No scenario requires glossary or principle changes that the current model