chore: cleanup after RenderDeploymentTemplate gating fix

[jeffmccune]

Parent Issue

Part of #386

Goal

Scan the repository for any dead code, stale comments, or outdated documentation introduced or made stale by the fix in #388. Also update the default CUE template in CreateTemplateModal to use the structured namespaced/cluster output format so that the preview actually works when opened.

Acceptance Criteria

• Default CUE template in create-template-modal.tsx uses the structured output format (produces valid namespaced output)
• No stale comments or dead code related to the render query
• make test passes

Implementation Notes

Files to review

• frontend/src/components/create-template-modal.tsx — Update DEFAULT_CUE_TEMPLATE to use the structured namespaced/cluster format documented in docs/cue-template-guide.md
• frontend/src/queries/deployment-templates.ts — Verify no stale comments
• frontend/src/routes/_authenticated/projects/$projectName/templates/$templateName.tsx — Verify the template detail page still works correctly with the updated hook signature

Dependencies

Depends on #388 (the gating fix must be in place first).

[jeffmccune]

Working on this issue.

• Agent path: /Users/jeff/workspace/holos-run/holos-console-agent-1
• Hostname: Jeffs-MacBook.local
• Branch: feat/389-cleanup-after-render-deployment-template-gating