docs: point GitHub links at the product repo and add a star CTA (#16)

## What

Two changes, one goal: stop showing a 0-star repo on the site and put
the real social proof in front of visitors.

1. **Header GitHub button** (`mkdocs.yml`): `repo_url`/`repo_name` now
point at the product repository `commit-check/commit-check` (70★ / 16
forks) instead of this documentation repository (0★ / 0 forks). Visitors
are users of the product — the star/fork counts and the star entry point
belong to the product repo.
2. **`edit_uri` is now absolute** so "Edit this page" keeps linking back
to `commit-check/commit-check.com`, where the pages actually live.
3. **Homepage hero** (`docs/overrides/home.html`): added a secondary "⭐
Star on GitHub" button next to "Get started", turning the passive header
icon into an active ask.

## Why

The docs repo is an implementation detail; nobody who finds the site
from search wants to star or contribute to it. The header was showing 0
stars — the worst first impression a new project can make — while the
real repo's 70 stars stayed invisible.

## Verification

- `mkdocs build --strict` passes (mkdocs-ng-material 9.7.7)
- Built HTML confirms: header links to
`github.com/commit-check/commit-check`, edit links still resolve to
`commit-check.com/edit/main/docs/...`, both hero buttons render


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Added a “Star on GitHub” button to the documentation homepage for
quick access to the project repository.

* **Documentation**
* Updated repository links and edit-page settings for more accurate
documentation navigation.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: shenxianpeng

docs/overrides/home.html

@@ -13,6 +13,12 @@ <h1 id="commit-check">Commit Check</h1>
                     <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="m13.13 22.19-1.63-3.83c1.57-.58 3.04-1.36 4.4-2.27zM5.64 12.5l-3.83-1.63 6.1-2.77C7 9.46 6.22 10.93 5.64 12.5M21.61 2.39S16.66.269 11 5.93c-2.19 2.19-3.5 4.6-4.35 6.71-.28.75-.09 1.57.46 2.13l2.13 2.12c.55.56 1.37.74 2.12.46A19.1 19.1 0 0 0 18.07 13c5.66-5.66 3.54-10.61 3.54-10.61m-7.07 7.07c-.78-.78-.78-2.05 0-2.83s2.05-.78 2.83 0c.77.78.78 2.05 0 2.83s-2.05.78-2.83 0m-5.66 7.07-1.41-1.41zM6.24 22l3.64-3.64c-.34-.09-.67-.24-.97-.45L4.83 22zM2 22h1.41l4.77-4.76-1.42-1.41L2 20.59zm0-2.83 4.09-4.08c-.21-.3-.36-.62-.45-.97L2 17.76z"></path></svg>
                 </span>
             </a>
+            <a class="md-button" href="https://github.com/commit-check/commit-check" title="Star us on GitHub">
+                <span class="twemoji">
+                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 17.27 18.18 21l-1.64-7.03L22 9.24l-7.19-.61L12 2 9.19 8.63 2 9.24l5.46 4.73L5.82 21z"></path></svg>
+                </span>
+                Star on GitHub
+            </a>
         </p>
     </div>
 {% endblock %}

mkdocs.yml

@@ -8,12 +8,14 @@ site_description: >-
 site_author: shenxianpeng
 copyright: Copyright © 2022 - 2026 Commit Check
 
-# The documentation covers a family of repositories, so the links point at the
-# organisation rather than at any single one. edit_uri is absolute for the same
-# reason: the pages live here, not in the repository they document.
-repo_url: https://github.com/commit-check/commit-check.com
-repo_name: commit-check/commit-check.com
-edit_uri: edit/main/docs/
+# The header links to the product repository, not to this documentation repo:
+# visitors who reach the site from a search or a link are users of commit-check
+# itself, and the star/fork counts and the "star" entry point belong to it. The
+# pages themselves live here, so edit_uri is an absolute URL pointing back at
+# this repository.
+repo_url: https://github.com/commit-check/commit-check
+repo_name: commit-check/commit-check
+edit_uri: https://github.com/commit-check/commit-check.com/edit/main/docs/
 
 docs_dir: docs