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/unifiedResult.ts

@@ -0,0 +1,38 @@
+import type { ResultType } from './enums'
+import type { Property } from './property'
+import type { FutureSignal } from './futureSignal'
+import type { Match } from './match'
+
+// ── Unified Match Result (discriminated union) ────────────────────────────────
+// Wraps the three result types so UI components can handle all three paths
+// without type confusion. Discriminate on `resultType`.
+
+interface UnifiedResultBase {
+  matchId: string
+  needId: string
+  matchScore: number
+  resultType: ResultType
+}
+
+export interface VerifiedPortfolioResult extends UnifiedResultBase {
+  resultType: 'VERIFIED_PORTFOLIO'
+  property: Property
+  match: Match
+}
+
+export interface ExternalMarketResult extends UnifiedResultBase {
+  resultType: 'EXTERNAL_MARKET'
+  property: Property
+  match: Match
+}
+
+export interface FutureAvailabilityResult extends UnifiedResultBase {
+  resultType: 'FUTURE_AVAILABILITY'
+  signal: FutureSignal
+  match: Match
+}
+
+export type UnifiedMatchResult =
+  | VerifiedPortfolioResult
+  | ExternalMarketResult
+  | FutureAvailabilityResult