Add Web4/DHT domain resolution methods (#15)

- Add resolveWeb4ViaDht() for DHT-based domain resolution
- Add getContractFromDht() to retrieve contracts from DHT storage
- Improve getContractByHash() with JSDoc and proper return type

These methods support Web4/dApp functionality once the ZHTP node implements the corresponding endpoints (blocked by node Issue #113).

Endpoints:
- GET /api/v1/dht/web4/resolve/{domain}
- GET /api/v1/dht/contract/{contractId}
- GET /api/v1/blockchain/contract/{hash}

Fixes #9

Author: umwelt

src/core/zhtp-api-methods.ts

@@ -557,8 +557,12 @@ export abstract class ZhtpApiMethods extends ZhtpApiCore {
     return this.request<any>(endpoint);
   }
 
-  async getContractByHash(hash: string): Promise<any> {
-    return this.request<any>(`/api/v1/blockchain/contract/${hash}`);
+  /**
+   * Lookup contract by blockchain transaction hash
+   * @param hash - Deployment transaction hash
+   */
+  async getContractByHash(hash: string): Promise<SmartContract> {
+    return this.request<SmartContract>(`/api/v1/blockchain/contract/${hash}`);
   }
 
   async getContractById(contractId: string): Promise<SmartContract> {
@@ -569,6 +573,22 @@ export abstract class ZhtpApiMethods extends ZhtpApiCore {
     return this.request<DApp>(`/api/v1/web4/resolve/${encodeURIComponent(domainName)}`);
   }
 
+  /**
+   * Resolve Web4 domain via DHT network
+   * @param domain - Domain name (e.g., "example.zhtp")
+   */
+  async resolveWeb4ViaDht(domain: string): Promise<DApp> {
+    return this.request<DApp>(`/api/v1/dht/web4/resolve/${encodeURIComponent(domain)}`);
+  }
+
+  /**
+   * Get contract from DHT distributed storage
+   * @param contractId - Contract identifier
+   */
+  async getContractFromDht(contractId: string): Promise<SmartContract> {
+    return this.request<SmartContract>(`/api/v1/dht/contract/${contractId}`);
+  }
+
   // ==================== Blockchain Operations ====================
 
   async getBlockchainInfo(): Promise<any> {