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>

.claude/projects/-Users-Repositories-farhoodliquor-shannon/memory/MEMORY.md

@@ -0,0 +1,3 @@
+# Memory Index
+
+- [reference_arc_runners.md](reference_arc_runners.md) — ARC self-hosted runners in farhoodliquor K8s cluster (`runners-farhoodliquor`)

.claude/projects/-Users-Repositories-farhoodliquor-shannon/memory/reference_arc_runners.md

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+---
+name: ARC self-hosted runners
+description: farhoodliquor org has ARC runner scale set named "runners-farhoodliquor" in their K8s cluster for GitHub Actions CI/CD
+type: reference
+---
+
+The farhoodliquor GitHub org has Actions Runner Controller (ARC) deployed in their K8s cluster with a runner scale set named `runners-farhoodliquor`. The ARC configuration lives in a separate repo (not in shannon). Shannon CI workflows should target these self-hosted runners instead of GitHub-hosted runners to avoid free-tier runner minute limits.
+
+**How to apply:** When modifying `.github/workflows/` files, use `runs-on: runners-farhoodliquor` instead of `runs-on: ubuntu-latest`.