setup --host hermes prints instructions and installs nothing, while README promises ~/.hermes/skills/gstack-*/

## What happens

`README.md:114-123` lists Hermes among the hosts with "Skills install to `~/.hermes/skills/gstack-*/`". `setup --host hermes` (`setup:211-219`) prints:

```
Hermes integration uses the same model as OpenClaw — Hermes spawns
Claude Code sessions, and gstack provides methodology artifacts.
1. Tell your Hermes agent: 'install gstack for hermes'
2. Or generate artifacts: bun run gen:skill-docs --host hermes
```

and exits 0 having written nothing.

## Why the "spawn Claude Code" premise no longer needs to hold

The Hermes render the generator produces runs natively. Measured on Hermes 0.21.0:

- `gen:skill-docs --host hermes` writes `.hermes/skills/gstack-*/SKILL.md` with zero literal `~/.claude` paths; the preamble resolves `GSTACK_ROOT="$HOME/.hermes/skills/gstack"` and every `bin/`, `browse/dist`, `design/dist`, checklist and section through it.
- With `~/.hermes/skills/gstack` symlinked to the checkout, `bun` on the gateway's PATH, and a profile's `skills.external_dirs` pointing at the render directories, `hermes skills list` shows the skills enabled and `skill_view` loads them; the `bin/` tools resolve.
- Hermes does not run its skill scanner on `external_dirs`, so the quarantine that blocks a hub install does not apply on this path.

## Ask

Make `setup --host hermes` do what `--host codex` does: link the root (`~/.hermes/skills/gstack` → checkout), generate the render, and print the `external_dirs` entries a profile needs — or change the README row to say the host is not installed by `setup`. Either removes the three hand steps a Hermes deployment carries today.

## Measured on

gstack 1.68.2 at `51932ec`, Hermes 0.21.0 (upstream `22c5684b`), macOS arm64, bun 1.3.14.

Start with the Hermes branch in setup:211-219, compare it with the --host codex behavior, and review the README row at README.md:114-123. Run bun run gen:skill-docs --host hermes and verify that setup creates the root link, generates the render, and prints the required external_dirs entries.

Written by the indexing model from the issue text.