feat: add Task template, gh-cherry-usage skill, and migrate PR review to gh cherry

[EurFelux]

What this PR does

Before this PR:

• The gh-create-issue skill uses gh issue create, which does not support setting issue types
• No Task issue template exists
• No gh-cherry-usage skill exists for CLI reference

After this PR:

• Adds a Task issue template (.github/ISSUE_TEMPLATE/4_task.yml) for tracking work items
• Updates the gh-create-issue skill to use gh-cherry extension for automatic issue type assignment when the template defines a type field
• Adds gh-cherry-usage public skill as a usage guide for the gh cherry CLI extension
• Migrates PR review skill from gh pr-review to gh cherry, which provides a more complete review lifecycle with unified issue/diff/review commands

Why we need it and why it was done in this way

GitHub CLI (gh) does not natively support issue types (tracked in cli/cli#9696). The gh-cherry extension (EurFelux/gh-cherry) fills this gap by wrapping the GraphQL API, and also provides enhanced PR diff and review lifecycle commands that supersede the old gh-pr-review extension.

Migrating from gh-pr-review to gh-cherry also eliminates the license risk — gh-pr-review upstream has no license, while gh-cherry is MIT-licensed and can be safely integrated into the main repository.

The following tradeoffs were made:

• Depends on a third-party gh extension (gh-cherry) rather than calling GraphQL directly, for simplicity and maintainability

The following alternatives were considered:

• Calling gh api graphql directly in the skill — rejected because it's verbose and harder to maintain

Breaking changes

None.

Special notes for your reviewer

Install: gh extension install EurFelux/gh-cherry (v0.0.1 released)

Checklist

• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Documentation: A user-guide update was considered and is present (link) or not required. Check this only when the PR introduces or changes a user-facing feature or behavior.
• Self-review: I have reviewed my own code (e.g., via /gh-pr-review, gh pr diff, or GitHub UI) before requesting review from others

Release note

NONE

[EurFelux]

Note

This issue/comment/review was translated by Claude.

The enhanced PR diff can display explicit diff line numbers, reducing the unnecessary process of agents manually calculating line numbers, adding threads, and previewing through multiple trial and error attempts.

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Original Content

增强的pr diff 可以显示明确的 diff 行号，减少需要agent 手动计算行号后 add thread 又 preview，多次试错的不必要的过程。