feat: add similar neighborhood analysis

apps/web/src/lib/api.ts

@@ -366,9 +366,55 @@ export type NeighborhoodDetail = {
   profile: Neighborhood;
   current_score: NeighborhoodScore | null;
   monthly_metrics: NeighborhoodMonthlyMetric[];
+  similar_neighborhoods: SimilarNeighborhood[];
   watchlist_items: WatchlistItem[];
 };
 
+export type SimilarNeighborhoodCandidate = {
+  neighborhood_id: string;
+  area_id: string;
+  name: string;
+  area_name: string;
+  district: string;
+  built_year: number | null;
+  property_type: string;
+  metro_distance_m: number | null;
+  school_quality: string | null;
+  month: string;
+  investment_score: number;
+  recommendation: string;
+  transaction_price_psm: number;
+  annual_rent_yield_pct: number;
+  liquidity_score: number;
+  location_score: number;
+  building_age_score: number;
+};
+
+export type SimilarNeighborhood = {
+  neighborhood_id: string;
+  area_id: string;
+  name: string;
+  area_name: string;
+  district: string;
+  built_year: number | null;
+  property_type: string;
+  metro_distance_m: number | null;
+  school_quality: string | null;
+  investment_score: number;
+  recommendation: string;
+  transaction_price_psm: number;
+  annual_rent_yield_pct: number;
+  similarity_score: number;
+  relative_price_pct: number;
+  reasons: string[];
+};
+
+export type SimilarNeighborhoodResponse = {
+  target: SimilarNeighborhoodCandidate;
+  month: string;
+  items: SimilarNeighborhood[];
+};
+
 export type ComparisonMetricValue = {
   id: string;
   value: number | null;
@@ -444,6 +490,16 @@ export async function fetchNeighborhoodDetail(
   );
 }
 
+export async function fetchSimilarNeighborhoods(
+  neighborhoodId: string,
+  month: string,
+  limit = 8,
+): Promise<SimilarNeighborhoodResponse> {
+  return fetchJson(
+    `/api/v1/neighborhoods/${encodeURIComponent(neighborhoodId)}/similar?month=${encodeURIComponent(month)}&limit=${limit}`,
+  );
+}
+
 export async function fetchAreaComparison(
   areaIds: string[],
   month: string,