test(integration): repair IntegrationTests harness and stale API-key test

- ScadaLinkWebApplicationFactory removed the AkkaHostedService SINGLETON, not
  just its IHostedService registration, so IClusterNodeProvider's factory
  (Program.cs) could not resolve it — 10 tests failed at host build. Now removes
  only the factory-registered IHostedService descriptors and keeps the singleton.
- Configure an LDAP service account so ResolveUserDnAsync does search-then-bind
  against GLAuth (whose DN layout the no-service-account fallback DN never
  matched), fixing LoginEndpoint_WithValidLdapCredentials.
- IntegrationSurfaceTests: ApiKeyValidator now matches keys by HMAC hash over
  GetAllApiKeysAsync (ConfigurationDatabase-012); the test mocked the removed
  GetApiKeyByValueAsync path. Suite now 64/64.

tests/ScadaLink.IntegrationTests/IntegrationSurfaceTests.cs

@@ -33,7 +33,9 @@ public class IntegrationSurfaceTests
             TimeoutSeconds = 30
         };
 
-        repository.GetApiKeyByValueAsync("key-value-123").Returns(key);
+        // ConfigurationDatabase-012: the validator fetches every key and matches
+        // the candidate by HMAC hash in constant time (no secret-equality lookup).
+        repository.GetAllApiKeysAsync().Returns(new List<ApiKey> { key });
         repository.GetMethodByNameAsync("getStatus").Returns(method);
         repository.GetApprovedKeysForMethodAsync(10).Returns(new List<ApiKey> { key });