[Task] Migrate files, update prompt references, and add deprecation paths

[ashleyshaw]

Parent issue: #736

Template source: .github/ISSUE_TEMPLATE/01-task.md\nTemplate label: 📝 Task\nSpec source: .github/projects/active/refactor-migrate-prompts/openspec-strict/children/01-3-task-migrate-files-update-references-and-deprecations.md\n\n---\n## Template Base\n\n## Task Summary

Acceptance Criteria

• Task is clearly defined and actionable
• Task is relevant to project goals
• Documentation updated if needed
• Changelog entry prepared for PR if task completed via PR
• Correct branch prefix for PR: chore/ or task/

Steps / Checklist

Dependencies

Additional Context

---

Definition of Ready (DoR)

• Task described and scoped
• Estimate added if relevant

Definition of Done (DoD)

• Task completed and documented
• Changelog entry prepared for PR
• PR uses correct branch prefix

---\n\n---\n## Spec Details\n\n## template-map

• template_file: .github/ISSUE_TEMPLATE/01-task.md

Deliverables

1. Updated prompts/README.md with migrated prompt catalogue.
2. Updated .github/prompts/README.md clarifying control-plane-only scope.
3. Deprecation notes for legacy prompts that moved or merged.

Acceptance Criteria

• Both prompt READMEs reflect canonical boundaries.
• Legacy prompts include clear successor path notes where required.
• Link checks pass for prompt indexes and cross-references.
• Migration guidance is explicit and reproducible.

[linear-code]

LS-879

[ashleyshaw]

Completed.

Acceptance criteria evidence:

• prompts/README.md updated for canonical boundary and migration status.
• .github/prompts/README.md updated for control-plane scope and migration notice.
• Deprecation notices applied to all non-keep legacy prompts.

References:

• .github/projects/active/refactor-migrate-prompts/artifacts/01-3-migration-output.md
• .github/projects/active/refactor-migrate-prompts/children/01-3-migrate-files-update-cross-references-and-deprecations.md

[ashleyshaw]

Closing as complete. Evidence and artefacts linked in the latest comment.

[ashleyshaw]

Implemented in PR #748: #748 (merged).