fix(LLMO-4070): seed S3 config in IT harness to fix PATCH /sites/:id/:auditType 500s

Configuration is read from S3 (not PostgREST), so the dummy-config-bucket
was missing in MinIO, causing Configuration.findLatest() to throw on every
PATCH request and surface as a 500 in IT tests. Seed a minimal config with
all known handlers on harness startup.

Also adds the context.data null branch test for patchAuditForSite (100%
branch coverage on audits.js).

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

Author: noelruiz34

test/it/postgres/setup.js

@@ -14,7 +14,9 @@
 import { execSync } from 'child_process';
 import { fileURLToPath } from 'url';
 import path from 'path';
-import { S3Client, CreateBucketCommand, HeadBucketCommand } from '@aws-sdk/client-s3';
+import {
+  S3Client, CreateBucketCommand, HeadBucketCommand, PutObjectCommand,
+} from '@aws-sdk/client-s3';
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const COMPOSE_FILE = path.join(__dirname, 'docker-compose.yml');
@@ -86,6 +88,60 @@ async function ensureMinIoBucket() {
   }
 }
 
+/**
+ * Creates the MinIO config bucket and seeds the global SpaceCat configuration.
+ * Configuration is stored in S3 (not PostgREST), so PATCH /sites/:id/:auditType
+ * needs this object to resolve the registered handlers list.
+ */
+async function ensureMinIOConfigBucket() {
+  const s3 = new S3Client({
+    region: 'us-east-1',
+    endpoint: `http://localhost:${MINIO_PORT}`,
+    forcePathStyle: true,
+    credentials: { accessKeyId: 'minioadmin', secretAccessKey: 'minioadmin' },
+  });
+
+  const bucket = 'dummy-config-bucket';
+  try {
+    await s3.send(new HeadBucketCommand({ Bucket: bucket }));
+  } catch {
+    await s3.send(new CreateBucketCommand({ Bucket: bucket }));
+  }
+
+  const handler = { enabledByDefault: true, productCodes: ['spacecat'] };
+  const config = {
+    handlers: {
+      'alt-text': handler,
+      apex: handler,
+      'broken-backlinks': handler,
+      canonical: handler,
+      cwv: handler,
+      faqs: handler,
+      headings: handler,
+      hreflang: handler,
+      'internal-links': handler,
+      'llm-blocked': handler,
+      'meta-tags': handler,
+      'missing-structured-data': handler,
+      prerender: handler,
+      readability: handler,
+      sitemap: handler,
+      'structured-data': handler,
+      summarization: handler,
+      toc: handler,
+    },
+    jobs: [],
+    queues: { auditJobsQueue: 'https://sqs.us-east-1.amazonaws.com/000000000000/dummy' },
+  };
+
+  await s3.send(new PutObjectCommand({
+    Bucket: bucket,
+    Key: 'config/spacecat/global-config.json',
+    Body: JSON.stringify(config),
+    ContentType: 'application/json',
+  }));
+}
+
 /**
  * Starts PostgreSQL + PostgREST + MinIO via docker compose and waits for readiness.
  *
@@ -104,6 +160,7 @@ export async function startPostgres() {
   ]);
 
   await ensureMinIoBucket();
+  await ensureMinIOConfigBucket();
 
   return POSTGREST_URL;
 }