setup-openspeclisted

Set up [OpenSpec](https://github.com/Fission-AI/OpenSpec) for spec-driven development in this project. Steps: 1. Verify Node.js ≥ 20.19.0 is available. Run `node --version`. If Node is missing or older than 20.19.0, stop and tell the user to upgrade Node.js first. 2. Check whether the OpenSpec CLI is already installed globally: ```bash npm list -g @fission-ai/openspec --depth=0 ``` If it is not installed (command exits non-zero or output does not mention `@fission-ai/openspec`), install it: ```bash npm install -g @fission-ai/openspec@latest ``` 3. Run OpenSpec initialization in the current project directory: ```bash openspec init --tools claude ``` 4. Report what was done: - Whether openspec was already installed or newly installed - The output of `openspec init --tools claude` - The skills and commands that are now available (`/opsx:explore`, `/opsx:propose`, `/opsx:apply`, `/opsx:archive`)