refactor: rename all custom K8s components to hightower

Namespace, Temporal, router, PVCs, labels, and GHCR API image all
renamed from shannon-* to hightower-*. Upstream references preserved:
worker image (ghcr.io/farhoodliquor/shannon), .shannon/ dirs,
@shannon/worker package imports.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/api/src/services/scan-manager.ts

@@ -106,7 +106,7 @@ export async function listScans(
   const jobs = await listWorkerJobs(batchApi, config.k8sNamespace);
   for (const job of jobs) {
     const jobName = job.metadata?.name ?? '';
-    const workspace = job.metadata?.labels?.['shannon.io/workspace'] ?? jobName;
+    const workspace = job.metadata?.labels?.['hightower.io/workspace'] ?? jobName;
     const startTime = job.status?.startTime;
 
     results.push({