feat: add pricing quality controls

Add robust outlier detection, stale valuation metadata, and audited seller-scoped market-value overrides with migration and tests.

packages/contracts/pricing.js

@@ -26,6 +26,7 @@ export function toAdminMarketValuationDto({ valuation, observations }) {
     confidence: valuation.confidence,
     sourceCount: valuation.sourceCount,
     calculatedAt: toIsoString(valuation.calculatedAt),
+    stale: Date.now() - new Date(valuation.calculatedAt).getTime() > 7 * 24 * 60 * 60 * 1000,
     observations: observations.map(toAdminPricingObservationDto),
   };
 }

packages/validation/pricing.js

@@ -10,4 +10,10 @@ export const createPricingObservationSchema = z.object({
   conditionId: z.uuid(),
   sourceUrl: z.string().trim().url().optional(),
   qualityScore: z.int().min(0).max(100).optional(),
+}).strict();
+
+export const createMarketValueOverrideSchema = z.object({
+  valueMinor: z.int().nonnegative(),
+  currency: z.string().trim().regex(/^[A-Za-z]{3}$/).optional(),
+  reason: z.string().trim().min(3).max(1000),
 }).strict();