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/hooks/useUnifiedResults.ts

@@ -6,7 +6,6 @@ import { useSchattenmarktSignals } from './useSchattenmarktSignals'
 import type {
   UnifiedMatchResult,
   VerifiedPortfolioResult,
-  ExternalMarketResult,
   FutureAvailabilityResult,
 } from '../domain/unifiedResult'
 
@@ -64,24 +63,11 @@ export function useUnifiedResults(needId?: string) {
           ? (property.units?.find(u => u.id === match.unitId) ?? undefined)
           : undefined
 
-        if (rt === 'EXTERNAL_MARKET' || rt === 'MAISON_WORK') {
-          const result: ExternalMarketResult = {
-            matchId: match.id,
-            needId: match.needId,
-            matchScore: match.matchScore,
-            resultType: rt as 'EXTERNAL_MARKET' | 'MAISON_WORK',
-            property,
-            match,
-            unit: matchUnit,
-          }
-          return [result]
-        }
-
         const result: VerifiedPortfolioResult = {
           matchId: match.id,
           needId: match.needId,
           matchScore: match.matchScore,
-          resultType: 'VERIFIED_PORTFOLIO',
+          resultType: rt as 'VERIFIED_PORTFOLIO' | 'MAISON_WORK',
           property,
           match,
           unit: matchUnit,