chore: replace custom code-review command with pr-review-toolkit plugin

[benhigham]

Summary

• Deletes .claude/commands/code-review.md, now redundant with the pr-review-toolkit plugin's /pr-review-toolkit:review-pr command
• Updates AGENTS.md directory tree and README.md command table to remove the entry
• Updates update-command-file skill to reference security-review.md as the example PR review command

The code-review plugin (confidence-scored bug detection) remains enabled — only the custom command file is removed.

Closes #35

Test plan

• mise run check passes (format + lint)
• Verify no workflows reference command: code-review in other repos

[Copilot]

Pull request overview

This PR removes a redundant custom PR review command file now that the pr-review-toolkit plugin provides a richer PR review command, and updates repository documentation to reflect that removal.

Changes:

• Deleted .claude/commands/code-review.md (custom PR review command).
• Updated README.md and AGENTS.md to remove references to the deleted command file.
• Updated the update-command-file skill to use security-review.md as the example PR review command.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
README.md	Removes code-review from the documented command list.
AGENTS.md	Updates the .claude/commands/ directory tree to no longer list code-review.md.
.claude/skills/update-command-file/SKILL.md	Switches the example “PR review” command file reference from code-review.md to security-review.md.
.claude/commands/code-review.md	Deletes the redundant custom PR review command file.

Comments suppressed due to low confidence (1)

README.md:103

• The Claude Code Commands table removes code-review, but there’s no mention of the intended replacement (/pr-review-toolkit:review-pr). This leaves readers without a documented “default” PR review path (especially since security-review is narrower). Consider adding a brief note near this table pointing to the plugin command and clarifying it’s provided by pr-review-toolkit (not a .claude/commands/*.md file).

## Claude Code Commands

Reference command files live in `.claude/commands/`. Copy to your repo's `.claude/commands/`
directory and customise for your stack.

The Trigger column shows the intended workflow event — you must configure a workflow in your repo to
invoke these commands on the appropriate event.

| Command            | Purpose                                  | Trigger                  |
| ------------------ | ---------------------------------------- | ------------------------ |
| `renovate-review`  | Review Renovate dependency PRs           | PR open (renovate actor) |
| `test-gen`         | Generate missing tests for changed files | PR open                  |
| `security-review`  | Security-focused PR review               | PR open                  |
| `docs-sync`        | Keep docs accurate after code changes    | PR open                  |

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