feat(search): implement Search module with Typesense full-text & geo search

- TypesenseClient service with configurable connection
- Collection schema for listings with facets, geo-point, and Vietnamese text
- ListingIndexer service with PostGIS coordinate extraction for geo search
- CQRS commands: SyncListing, ReindexAll (batch with pagination)
- CQRS queries: SearchProperties (filters, sorting), GeoSearch (radius)
- Event handlers for listing.approved/updated/deactivated auto-sync
- REST endpoints: GET /search, GET /search/geo, POST /search/reindex (admin)
- DTOs with class-validator validation and pagination

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/search/domain/index.ts

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+export * from './value-objects';
+export * from './repositories';

apps/api/src/modules/search/domain/repositories/index.ts

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+export { SEARCH_REPOSITORY, type ISearchRepository, type ListingDocument, type SearchResult, type SearchParams } from './search.repository';

apps/api/src/modules/search/domain/repositories/search.repository.ts

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+export const SEARCH_REPOSITORY = Symbol('SEARCH_REPOSITORY');
+
+export interface ListingDocument {
+  id: string;
+  listingId: string;
+  propertyId: string;
+  title: string;
+  description: string;
+  propertyType: string;
+  transactionType: string;
+  priceVND: number;
+  pricePerM2: number | null;
+  areaM2: number;
+  bedrooms: number | null;
+  bathrooms: number | null;
+  floors: number | null;
+  direction: string | null;
+  address: string;
+  ward: string;
+  district: string;
+  city: string;
+  location: [number, number]; // [lat, lng]
+  agentId: string | null;
+  sellerId: string;
+  status: string;
+  publishedAt: number; // unix timestamp
+  viewCount: number;
+  saveCount: number;
+  projectName: string | null;
+  amenities: string[];
+}
+
+export interface SearchResult {
+  hits: ListingDocument[];
+  totalFound: number;
+  page: number;
+  perPage: number;
+  totalPages: number;
+  searchTimeMs: number;
+}
+
+export interface SearchParams {
+  query?: string;
+  filterBy?: string;
+  sortBy?: string;
+  page?: number;
+  perPage?: number;
+  geoDistanceField?: string;
+  geoPoint?: { lat: number; lng: number };
+  geoRadiusKm?: number;
+}
+
+export interface ISearchRepository {
+  indexDocument(doc: ListingDocument): Promise<void>;
+  indexDocuments(docs: ListingDocument[]): Promise<void>;
+  removeDocument(id: string): Promise<void>;
+  search(params: SearchParams): Promise<SearchResult>;
+  ensureCollection(): Promise<void>;
+  dropCollection(): Promise<void>;
+}

apps/api/src/modules/search/domain/value-objects/geo-filter.vo.ts

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+import { ValueObject } from '@modules/shared/domain/value-object';
+
+interface GeoFilterProps {
+  lat: number;
+  lng: number;
+  radiusKm: number;
+  propertyType?: string;
+  transactionType?: string;
+  priceMin?: number;
+  priceMax?: number;
+  sortBy?: 'distance' | 'price_asc' | 'price_desc' | 'date_desc';
+  page?: number;
+  perPage?: number;
+}
+
+export class GeoFilter extends ValueObject<GeoFilterProps> {
+  get lat(): number {
+    return this.props.lat;
+  }
+
+  get lng(): number {
+    return this.props.lng;
+  }
+
+  get radiusKm(): number {
+    return Math.min(this.props.radiusKm, 100);
+  }
+
+  get propertyType(): string | undefined {
+    return this.props.propertyType;
+  }
+
+  get transactionType(): string | undefined {
+    return this.props.transactionType;
+  }
+
+  get priceMin(): number | undefined {
+    return this.props.priceMin;
+  }
+
+  get priceMax(): number | undefined {
+    return this.props.priceMax;
+  }
+
+  get sortBy(): string {
+    return this.props.sortBy ?? 'distance';
+  }
+
+  get page(): number {
+    return this.props.page ?? 1;
+  }
+
+  get perPage(): number {
+    return Math.min(this.props.perPage ?? 20, 100);
+  }
+
+  static create(props: GeoFilterProps): GeoFilter {
+    return new GeoFilter(props);
+  }
+}

apps/api/src/modules/search/domain/value-objects/index.ts

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+export { SearchFilter } from './search-filter.vo';
+export { GeoFilter } from './geo-filter.vo';

apps/api/src/modules/search/domain/value-objects/search-filter.vo.ts

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+import { ValueObject } from '@modules/shared/domain/value-object';
+
+interface SearchFilterProps {
+  query?: string;
+  propertyType?: string;
+  transactionType?: string;
+  priceMin?: number;
+  priceMax?: number;
+  areaMin?: number;
+  areaMax?: number;
+  bedrooms?: number;
+  district?: string;
+  city?: string;
+  sortBy?: 'price_asc' | 'price_desc' | 'date_desc' | 'relevance' | 'distance';
+  page?: number;
+  perPage?: number;
+}
+
+export class SearchFilter extends ValueObject<SearchFilterProps> {
+  get query(): string | undefined {
+    return this.props.query;
+  }
+
+  get propertyType(): string | undefined {
+    return this.props.propertyType;
+  }
+
+  get transactionType(): string | undefined {
+    return this.props.transactionType;
+  }
+
+  get priceMin(): number | undefined {
+    return this.props.priceMin;
+  }
+
+  get priceMax(): number | undefined {
+    return this.props.priceMax;
+  }
+
+  get areaMin(): number | undefined {
+    return this.props.areaMin;
+  }
+
+  get areaMax(): number | undefined {
+    return this.props.areaMax;
+  }
+
+  get bedrooms(): number | undefined {
+    return this.props.bedrooms;
+  }
+
+  get district(): string | undefined {
+    return this.props.district;
+  }
+
+  get city(): string | undefined {
+    return this.props.city;
+  }
+
+  get sortBy(): string {
+    return this.props.sortBy ?? 'relevance';
+  }
+
+  get page(): number {
+    return this.props.page ?? 1;
+  }
+
+  get perPage(): number {
+    return Math.min(this.props.perPage ?? 20, 100);
+  }
+
+  static create(props: SearchFilterProps): SearchFilter {
+    return new SearchFilter(props);
+  }
+}