WIP: stage all uncommitted work — sprints 46-221, graduation headers, specialist fleet, test steps 909-1988

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sprint91_plan.md

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+# Sprint 91 Plan: Ecosystem Marketplace and Trust Exchange
+
+## Context
+
+With plugin and standards foundations in place, Sprint 91 introduces a curated
+marketplace for adapters, verifiers, and policy packs.
+
+---
+
+## Goals
+
+1. Add discoverable marketplace metadata and search
+2. Enforce trust tiers for published ecosystem artifacts
+3. Provide usage/quality signals for artifact selection
+4. Prevent unsafe artifact promotion in production pathways
+
+---
+
+## Steps
+
+### Step 1139: Marketplace catalog schema (12 tests)
+### Step 1140: Artifact trust-tier model (`community`, `verified`, `certified`) (10 tests)
+### Step 1141: Artifact quality scoring and ranking engine (10 tests)
+### Step 1142: Supply-chain integrity checks for marketplace artifacts (10 tests)
+### Step 1143: Artifact de-listing and quarantine workflow (10 tests)
+### Step 1144: Marketplace policy bindings for tenants (8 tests)
+### Step 1145: `whetstone_marketplace_search` MCP tool (8 tests)
+### Step 1146: `whetstone_get_artifact_trust_report` MCP tool (8 tests)
+### Step 1147: Marketplace governance report artifact (8 tests)
+### Step 1148: Sprint 91 integration summary + regression (8 tests)
+
+---
+
+## Trust Rule
+
+- Non-certified artifacts cannot be auto-enabled for Stable-tier workflows.