feat: initialize issue-spec workflow for Higress (#4059)

Signed-off-by: johnlanni <johnlanni@users.noreply.github.com>
Co-authored-by: johnlanni <johnlanni@users.noreply.github.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.agents/skills/issue-spec-github/SKILL.md

@@ -0,0 +1,58 @@
+---
+name: issue-spec-github
+description: Use GitHub CLI for GitHub issues, pull requests, CI runs, and API queries that issue-spec does not wrap.
+license: MIT
+compatibility: Requires GitHub CLI (gh).
+metadata:
+  author: issue-spec
+  version: "1.0"
+  generatedBy: "issue-spec"
+---
+
+# GitHub CLI
+
+Use the `gh` CLI to interact with GitHub repositories, issues, pull requests, CI, and API endpoints.
+
+## When To Use
+
+- Checking PR status, reviews, mergeability, or CI checks.
+- Creating, viewing, updating, closing, or commenting on GitHub issues.
+- Listing or inspecting pull requests, workflow runs, releases, labels, or repository metadata.
+- Calling GitHub API endpoints with `gh api` when issue-spec does not provide a dedicated command.
+
+## When Not To Use
+
+- Local git operations such as commit, branch, fetch, merge, or push. Use `git` directly.
+- Non-GitHub repositories. Use the matching provider CLI instead.
+- Complex code review across local diffs. Read the repository files directly and use issue-spec review commands for traceable findings.
+
+## Setup
+
+```bash
+gh auth login
+gh auth status
+```
+
+## Common Commands
+
+```bash
+gh issue list --repo owner/repo --state open
+gh issue view 42 --repo owner/repo --json number,title,state,url,body
+gh issue comment 42 --repo owner/repo --body "Comment body"
+
+gh pr list --repo owner/repo
+gh pr view 17 --repo owner/repo --json number,title,state,headRefName,baseRefName,url
+gh pr checks 17 --repo owner/repo
+
+gh run list --repo owner/repo --limit 10
+gh run view <run-id> --repo owner/repo --log-failed
+
+gh api repos/owner/repo/labels --jq '.[].name'
+```
+
+## Notes
+
+- Always pass `--repo owner/repo` when the current directory is not definitely inside the target repository.
+- Use GitHub URLs directly when convenient, for example `gh pr view https://github.com/owner/repo/pull/17`.
+- Prefer structured output with `--json` and `--jq` when another command or agent step consumes the result.
+- issue-spec owns the proposal, design, implement, typed comment, review, verify, and archive workflow state. Use `gh` for adjacent GitHub operations that are outside issue-spec's command surface.