feat(domain): F004 – expand domain model layer

- need.ts: add SizeRange, MustHaveCriterion, WeightedPreference types; extend Need with desiredLocation, sizeRange, mustHaveCriteria, weightedPreferences, status
- futureSignal.ts: add SignalEvidence type; extend FutureSignal with title, evidence, matchabilityScore, reviewStatus
- aiOutput.ts: new AIOutput entity with type, inputHash, outputJson, provider/model/promptVersion/schemaVersion, reviewStatus
- activityEvent.ts: new ActivityEvent entity with actorId, action, entityType, entityId, timestamp, metadata
- unifiedResult.ts: discriminated union (VerifiedPortfolioResult | ExternalMarketResult | FutureAvailabilityResult)
- index.ts: export all three new files
- Properties.tsx: add LIGHT_INDUSTRIAL + UNKNOWN cases to exhaustive switches

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

src/domain/futureSignal.ts

@@ -1,4 +1,4 @@
-import type { SignalType, RiskLevel } from './enums'
+import type { SignalType, RiskLevel, ReviewStatus } from './enums'
 
 export interface SignalSource {
   type: 'PRESS' | 'CONSTRUCTION_PERMIT' | 'JOB_POSTING' | 'COMPANY_REPORT' | 'MARKET_DATA' | 'MANUAL'
@@ -7,6 +7,12 @@ export interface SignalSource {
   credibility: 'LOW' | 'MEDIUM' | 'HIGH'
 }
 
+export interface SignalEvidence {
+  summary: string
+  sourceUrls?: string[]
+  extractedAt?: string
+}
+
 export interface FutureSignal {
   id: string
   signalType: SignalType
@@ -30,4 +36,10 @@ export interface FutureSignal {
   organizationId?: string
   createdAt: string
   updatedAt: string
+
+  // F004 additions
+  title?: string                       // short human-readable headline
+  evidence?: SignalEvidence            // structured evidence block
+  matchabilityScore?: number           // 0–100: how well this signal can be matched to needs
+  reviewStatus?: ReviewStatus
 }