fix(tests): resolve 4 failing test suites and patch lodash vulnerability

Test fixes (type mismatches introduced by V&V resolution changes):
- HealthDetailedController.test.ts: replace pool/makePool with dbProbe/makeDbProbe
  to match refactored HealthDetailedDeps interface (Pool → DbProbe abstraction)
- EventPublisher.test.ts: pass all 4 required constructor args to WebhookDeliveryWorker
  mock (pool, vaultClient, redisClient, redisUrl) — was passing only 1
- MarketplaceService.test.ts: IAgent.did/didCreatedAt are string|undefined (not null);
  fix makeAgent defaults and makeAgent({did:null}) call; fix type assertion to unknown first
- OIDCTrustPolicyService.test.ts: ICreateTrustPolicyRequest.branch is string|undefined
  (not nullable); replace all branch:null with branch:undefined

Security fix:
- npm audit fix: lodash ≤4.17.23 (HIGH) → patched; 0 vulnerabilities remaining

Result: 50/50 test suites pass, 722/722 tests pass, 0 vulnerabilities

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package-lock.json

@@ -6202,9 +6202,9 @@
       }
     },
     "node_modules/lodash": {
-      "version": "4.17.23",
-      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.23.tgz",
-      "integrity": "sha512-LgVTMpQtIopCi79SJeDiP0TfWi5CNEc/L/aRdTh3yIvmZXTnheWpKjSZhnvMl8iXbC1tFg9gdHHDMLoV7CnG+w==",
+      "version": "4.18.1",
+      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.18.1.tgz",
+      "integrity": "sha512-dMInicTPVE8d1e5otfwmmjlxkZoUpiVLwyeTdUsi/Caj/gfzzblBcCE5sRHV/AsjuCmxWrte2TNGSYuCeCq+0Q==",
       "license": "MIT"
     },
     "node_modules/lodash.defaults": {