Add gh.sh wrapper for gh CLI commands in issue triage workflows

[OctavianGuzu]

Adds a gh.sh wrapper script that provides a controlled interface to the gh CLI, allowing only specific subcommands (issue view, issue list, search issues, label list) and flags (--comments, --state, --limit, --label). Updates the /label-issue command and documentation to use the wrapper.

[claude]

PR Review Summary

Good idea to wrap gh CLI with an allowlist — this is a sound defense-in-depth approach that reduces the allowed-tools surface area nicely. The core allowlist logic is correct and the case + flag-check pattern is straightforward.

Key findings (inline comments posted):

1. Cross-repo search exposure — gh search issues accepts GitHub search qualifiers like repo:other-org/private-repo as positional args, which bypass the wrapper flag validation. Consider pinning --repo to scope operations to the current repo.

2. Silent failures — All rejection paths use bare exit 1 with no stderr output. Since Claude is the consumer, diagnostic messages would help it self-correct.

3. Missing argument-count validation — 0 or 1 args fall through to the case default silently. An explicit check would be clearer.

4. docs/solutions.md example is broken for copy-paste users — The workflow references ./scripts/gh.sh but has no actions/checkout step and no guidance that users must copy the scripts into their own repos.

Additional observations:

• No tests were added. This repo has a strong pattern of testing security-boundary code (permissions.test.ts, sanitizer.test.ts, github-file-ops-path-validation.test.ts). A shell script that enforces an allowlist of commands deserves similar coverage — particularly the must-reject cases (gh auth token, gh repo delete, disallowed flags on allowed subcommands, etc.).

• issue list is supported by the script but not documented in either label-issue.md or solutions.md. Minor inconsistency.

• No performance concerns. The bash overhead is negligible compared to gh network I/O.