fix(sync): clean legacy Codex skill duplicates

[Mozurok]

Summary

<2-4 sentences describing what this PR changes.>

Type of change

• New command (commands/<name>.md)
• Edit to existing command
• Shared block (commands/_shared/)
• Spec edit (WORKFLOW_OPERATING_SYSTEM.md)
• Documentation (README, FAQ, ROADMAP, etc.)
• Template (templates/)
• Script (scripts/)
• CI / GitHub Actions (.github/workflows/)
• Architecture Decision Record (docs/adr/)
• Eval scenario (evals/scenarios/)
• Other (specify)

Related issue

Closes #, or "no related issue" if standalone.

Checklist

• I have read CONTRIBUTING.md.
• I have signed the CLA when prompted by CLA Assistant on this PR.
• I ran ./scripts/lint-commands.sh locally and it passes.
• I followed the project's style guide (no em-dash, English for normative content, etc.).
• If I added a new command, I registered it in all four registries (lint fails on any gap):
  • the cluster bullet list under ## Command categories in WORKFLOW_OPERATING_SYSTEM.md
  • the ## Command roles index in WORKFLOW_OPERATING_SYSTEM.md
  • wos/command-roles.md
  • the COMMAND_PROMPT_STUBS.md table (with a minimal prompt example)
• If I added or edited a command, I regenerated the derived artifacts (never hand-edited):
  • ran python3 ./scripts/build-command-catalog.py (regenerates the README ## Command catalog and docs/command-catalog.*)
  • ran ./scripts/build-agent-skills.sh (regenerates .claude/skills/<name>/SKILL.md)
• If I edited a commands/_shared/<name>.md block, I ran ./scripts/sync-shared-blocks.sh to propagate it into every command that references it.
• If I added an ADR or an eval scenario, I added its index row (docs/adr/README.md for an ADR, evals/README.md for a scenario).
• If I changed an artifact count, I updated its <!-- count:KIND -->N<!-- /count --> marker to match the on-disk count.
• If I changed normative behavior (the spec or command contract), I added an ADR under docs/adr/.
• If this is a breaking change, I updated CHANGELOG.md under "Breaking changes" and bumped version per SemVer.
• I did not include any client names, absolute paths from my home directory, or other private information.

Notes for the maintainer

<Anything the maintainer should know during review: design tradeoffs you considered, alternatives you rejected, follow-ups intentionally deferred, etc.>