docs(maintainers): list website/ in the docs map and align CONTRIBUTING

Setup, configuration and deployment docs live in website/, which is
published as the docs site, but the map sent them to /docs and did not
list website/ at all. Add it, and drop the "when those paths are used"
hedge on /specs, which exists.

CODEOWNERS has no rules until #593 settles the per-area map; say so
instead of describing reviewers it does not list.

CONTRIBUTING.md still had a single maintainer curating main, which the
Release Maintainer section replaces. Name the Product Owner's GitHub
account and say where a community proposal starts, matching the
existing issue forms.

docs/maintainers/documentation.md

@@ -7,8 +7,9 @@ Repository Markdown is the canonical source for project documentation. A public
 | Location | Purpose |
 |---|---|
 | `/design` | Product intent, proposals, and accepted decisions (when those paths are used) |
-| `/specs` | Technical contracts and invariants (when those paths are used) |
-| `/docs` | User, developer, architecture, security, deployment, and maintainer guidance |
+| `/specs` | Technical contracts and invariants |
+| `/website` | User, setup, configuration, and deployment guidance (published as the docs site) |
+| `/docs` | Developer, architecture, security, and maintainer guidance |
 | Root Markdown | Discoverable entry points and policies |
 
 Keep root documents easy to find:
@@ -16,6 +17,7 @@ Keep root documents easy to find:
 - `README.md`
 - `CONTRIBUTING.md`
 - `SECURITY.md`
+- `THREAT_MODEL.md`
 
 Not every named directory exists today; do not invent a parallel documentation store just to match this map.