docs: name the static lists a new skill still needs and the Codex metadata file

From the ship documentation audit: CONTRIBUTING's new-skill checklist said no
static list needs a row, which this PR disproved (lib/doctor-components.ts
SKILL_REQUIREMENTS and the catalog rows); the host comparison table and
docs/ADDING_A_HOST.md gain the agents/openai.yaml default_prompt source; a blank
line before the new docs/unattended.md grant heading.

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

docs/ADDING_A_HOST.md

@@ -453,6 +453,7 @@ Key fields:
 | `frontmatter.descriptionLimitBehavior` | `error` (fail build), `truncate`, `warn` |
 | `frontmatter.conditionalFields` | Add fields based on template values (e.g., sensitive → disable-model-invocation) |
 | `frontmatter.renameFields` | Rename template fields (e.g., voice-triggers → triggers) |
+| `generation.generateMetadata` | Emit `agents/openai.yaml` beside each skill (Codex only today; the format is hardcoded in `gen-skill-docs.ts`). Its `default_prompt` comes from the template's `codex_default_prompt:` frontmatter key, else `Use <name> for this task.` |
 | `pathRewrites` | Literal replaceAll on content. Order matters. Replaces the derived trio. |
 | `extraPathRewrites` | (defineHost input only) Appended after the derived trio. |
 | `toolRewrites` | Rewrite Claude tool names (e.g., "use the Bash tool" → "run this command") |

docs/unattended.md

@@ -478,6 +478,7 @@ fix. `GSTACK_ALLOW_UNSUPPORTED_RUNTIME=1` admits anyway (`INSTALL_VERDICT:
 overridden`), recorded as a deviation. TypeScript entrypoints use
 `checkInstallAdmission` from `lib/install-verdict.ts`; the Bash side is
 `bin/gstack-install-verdict.sh`. See [capy-install.md](capy-install.md#the-launch-line).
+
 ## What an unattended session may do
 
 A parent that starts a skill with `GSTACK_SESSION_KIND=unattended` grants it