feat: remove EXTERNAL_MARKET result type entirely

All external market properties now surface as VERIFIED_PORTFOLIO.
Removes the type from enums, domain types, mock data, matching engine,
components, hooks, and tests — zero user-visible distinction remains.

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

src/features/matching/scoreCalculator.ts

@@ -499,8 +499,6 @@ export function calcConfidenceModifier(property: Property): number {
   let mod = 0
   if (property.resultType === ResultType.FUTURE_AVAILABILITY) {
     mod += CONFIDENCE_MODIFIER.FUTURE_AVAILABILITY
-  } else if (property.resultType === ResultType.EXTERNAL_MARKET) {
-    mod += CONFIDENCE_MODIFIER.EXTERNAL_MARKET
   } else if (property.resultType === ResultType.MAISON_WORK) {
     mod += CONFIDENCE_MODIFIER.MAISON_WORK
   } else {