fix(runbooks): align roster references with rendered agent ids

[atillayedek]

What does this PR do?

Agent Information (if adding/modifying an agent)

• Agent Name:
• Category:
• Specialty:

Checklist

• Follows the agent template structure from CONTRIBUTING.md
• Includes YAML frontmatter with name, description, color
• Has concrete code/template examples (for new agents)
• Tested in real scenarios
• Proofread and formatted correctly

[msitarzewski]

Thank you, @atillayedek, and for adding a regression test. We're keeping file stems in runbooks.json, though: the Agency Agents desktop app identifies agents by filename stem, so name-derived ids would stop its runbook deploys from resolving. The full reasoning is on #1027: #1027 (comment). Closing for that reason, with thanks.