fix: add missing NVI_TENANT environment variable to e2e test HAPI container

The fake-nvi HAPI FHIR server requires both NVI_AUDIENCE and NVI_TENANT
environment variables to properly configure the NVI partition. The test
harness was missing NVI_TENANT, causing partition validation errors when
searching for DocumentReferences through the NVI Gateway.

This aligns the e2e test configuration with the docker-compose.yml setup
which already includes both environment variables.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: rolandgroen

test/e2e/harness/hapi.go

@@ -27,6 +27,7 @@ func startHAPI(t *testing.T, dockerNetworkName string) *url.URL {
 			"hapi.fhir.delete_expunge_enabled": "true",
 			"hapi.fhir.allow_multiple_delete":  "true",
 			"NVI_AUDIENCE":                     "nvi",
+			"NVI_TENANT":                       "nvi",
 		},
 		WaitingFor: wait.ForHTTP("/fhir/DEFAULT/Account"),
 		LogConsumerCfg: &testcontainers.LogConsumerConfig{