refactor: rename custom components from shannon-* to hightower-*

Renames API server, worker jobs, credentials secret, and workspaces
PVC to use the hightower prefix. Upstream Shannon names (namespace,
Temporal service, package imports, .shannon/ dir) are unchanged.

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

apps/api/infra/base/service.yaml

@@ -1,11 +1,11 @@
 apiVersion: v1
 kind: Service
 metadata:
-  name: shannon-api
+  name: hightower-api
   namespace: shannon
 spec:
   selector:
-    app: shannon-api
+    app: hightower-api
   ports:
     - name: http
       port: 3000