Enable the OpenCode service on both desktop and laptop hosts.
Import the opencode module into the home configuration and provide
settings, plugins, extra packages, and skill definitions for full
functionality.
- Set `chatgpt.enable = true` for both Garand‑Desktop and Garand‑Laptop.
- Rename `modules/home/codex.nix` to `modules/home/codex/default.nix`.
- Add `mutableSettings = true` and import `plugins.nix` in the Codex
module.
- Introduce `modules/home/codex/plugins.nix` defining Codex plugins and
marketplaces.
- Update `modules/home/default.nix` to import the new Codex directory.
- Refresh ChatGPT desktop entry icon SHA256 hash.
GarandPLG