Add proof-measure client + bump to 1.4.0

proof-measure is a separate, public, unauthenticated Dragonchain service. Adds:
- UnauthHttpClient: HMAC-free transport mirroring DragonchainClient (timeout,
  agent, redirect refusal).
- ProofMeasureClient: getSecurity / report / health; default base URL
  https://proof-measure.dragonchain.com. Standalone (new ProofMeasureClient())
  and via DragonchainSDK.proofMeasure.
- Proof-measure types (decimals as strings, timestamps as numbers).
- jest tests.

src/proofMeasure.ts

@@ -0,0 +1,69 @@
+/**
+ * Client for the Dragonchain proof-measure service — the measured-immutability
+ * / "securedBy" metric for L1–L5 verification chains.
+ *
+ * proof-measure is a separate, public, UNauthenticated service (no API keys),
+ * so this client needs only a base URL. It exposes a network's accumulated
+ * security as both a raw measure (cumulative hashes / stake-seconds) and a USD
+ * valuation, plus a per-transaction "securedBy" report over interchain anchors.
+ */
+
+import { UnauthHttpClient, UnauthClientConfig } from './unauthHttpClient';
+import {
+  ContentType,
+  ProofMeasureSecurityResult,
+  ProofMeasureReportRequest,
+  ProofMeasureTransactionReport,
+  ProofMeasureHealthResponse,
+} from './types';
+
+/** Public production proof-measure endpoint. */
+export const PROOF_MEASURE_DEFAULT_BASE_URL = 'https://proof-measure.dragonchain.com';
+
+export class ProofMeasureClient {
+  private client: UnauthHttpClient;
+
+  /**
+   * @param clientOrConfig - an existing UnauthHttpClient, a config object, or
+   * nothing. With no argument (or no baseURL) the public production endpoint is
+   * used, so `new ProofMeasureClient()` works with zero configuration.
+   */
+  constructor(clientOrConfig?: UnauthHttpClient | UnauthClientConfig) {
+    if (clientOrConfig instanceof UnauthHttpClient) {
+      this.client = clientOrConfig;
+    } else {
+      this.client = new UnauthHttpClient({
+        baseURL: clientOrConfig?.baseURL || PROOF_MEASURE_DEFAULT_BASE_URL,
+        timeout: clientOrConfig?.timeout,
+        agent: clientOrConfig?.agent,
+      });
+    }
+  }
+
+  /**
+   * Returns the security a public network (network = 'BTC' or 'ETH') has
+   * accumulated since the given unix timestamp, as a raw measure + USD
+   * valuation. Omit `since` (or pass <= 0) to use the service default window.
+   */
+  async getSecurity(network: string, since?: number): Promise<ProofMeasureSecurityResult> {
+    const query = since && since > 0 ? `?since=${since}` : '';
+    return this.client.get<ProofMeasureSecurityResult>(`/api/v1/security/${network}${query}`);
+  }
+
+  /**
+   * Computes the per-transaction "securedBy" report for the supplied interchain
+   * anchors: each anchor's raw + USD security since it was placed, plus totals.
+   */
+  async report(request: ProofMeasureReportRequest): Promise<ProofMeasureTransactionReport> {
+    return this.client.post<ProofMeasureTransactionReport>(
+      '/api/v1/report',
+      ContentType.JSON,
+      request
+    );
+  }
+
+  /** Reports service liveness and DB reachability. */
+  async health(): Promise<ProofMeasureHealthResponse> {
+    return this.client.get<ProofMeasureHealthResponse>('/api/v1/health');
+  }
+}