git clone + setup fails: skill symlinks not created when bun is not pre-installed

[mmporong]

Summary

When installing gstack via git clone ... && ./setup, the setup script fails immediately if bun is not installed, leaving no skill symlinks in ~/.claude/skills/. The user is told to install bun manually, but even after installing bun, they must know to re-run ./setup — which isn't obvious.

As a result, invoking any gstack sub-skill (e.g., /office-hours) returns Unknown skill: office-hours because the symlinks were never created.

Steps to Reproduce

1. Fresh machine without bun installed
2. Run: git clone https://github.com/garrytan/gstack.git ~/.claude/skills/gstack && cd ~/.claude/skills/gstack && ./setup
3. Setup fails with: Error: bun is required but not installed.
4. Install bun manually: curl -fsSL https://bun.sh/install | bash
5. Bun is not yet in PATH for the current shell session
6. Re-run ./setup — still fails unless user manually exports PATH
7. Even after fixing PATH and re-running setup, the user has already moved on and tries /office-hours → Unknown skill

Expected Behavior

Either:

• Option A: setup auto-installs bun if missing (the script already prints the install command, could just run it)
• Option B: setup detects bun was just installed to ~/.bun/bin/ and adds it to PATH for the current invocation
• Option C: The README/install instructions make it explicit that bun must be installed and in PATH before running setup

Environment

• Windows 11 (MSYS2/Git Bash)
• bun v1.3.11 (installed after initial setup failure)
• gstack latest (cloned 2026-03-25)