feat(host): real `--host hermes` autoinstaller (currently only prints instructions)

## Real `--host hermes` autoinstaller (currently only prints instructions)

`./setup --host hermes` today only prints two integration tips and exits without writing any artifacts. That makes Hermes a second-class host vs Claude Code (`./setup`) and Codex (`./setup --host codex`), even though `bun run gen:skill-docs --host hermes` already generates a complete 45-skill `.hermes/skills/` tree.

### Current behavior
```
$ ./setup --host hermes
Hermes integration uses the same model as OpenClaw — Hermes spawns
Claude Code sessions, and gstack provides methodology artifacts.

To integrate gstack with Hermes:
1. Tell your Hermes agent: 'install gstack for hermes'
2. Or generate artifacts: bun run gen:skill-docs --host hermes
```

### Proposed behavior
1. Detect active Hermes profile via `hermes profile list` (or honor `HERMES_PROFILE` env).
2. Run `bun install` + `bun run gen:skill-docs --host hermes` automatically.
3. Copy `.hermes/skills/*` into `~/.hermes/profiles//skills/gstack-pack/`.
4. Add a `gstack` section to `~/.hermes/profiles//config.yaml` listing the 45 skill names.
5. Print a confirmation table (skill count, profile, install path).

### Why
Hermes is in the agent table on the README, but the install lane is the only one that does not actually install. Closing this gap unlocks Hermes-native deployment of the full gstack workflow without users having to copy directories by hand.

### Acceptance
- `./setup --host hermes` exits 0 with all 45 skills present in the profile's skills dir.
- `hermes skills list` shows the 45 gstack skills.
- README "Other AI Agents" table updates to remove the asterisk on Hermes.

I have a working implementation living locally and can open a PR if there's interest.