docs: lead the home page with commit policy as code for teams and AI agents (#51)

Before: the home page said what Commit Check checks but never what it
is. The meta description opened with "Catch bad commits before they
merge." The site description opened with "Enforce commit message, branch
naming, author and signoff standards".

After:
- The hero's lede opens with a bold **Commit policy as code for teams
and AI agents.** The headline above it is unchanged.
- The home page's meta description opens with the same line.
- The site description opens with it too.

How: this changes three strings in `docs/index.md` and `mkdocs.yml`. The
search title stays "Commit message & branch name linter for Git",
because that is what people search for.

Checks:
- `mkdocs build --strict` passes. Social cards were off for that build,
since Google Fonts is unreachable from the build machine.
- `python -m pytest tests/` passes against commit-check 2.18.3, which is
the latest release on PyPI. Pins and changelog are already in step.
- Screenshots of the built hero at 1280px and 390px wide show the bold
line leading the lede with no wrapping problems.

Companion PRs put the same line at the front of the org profile, the
Action and the MCP server.



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

## Summary by CodeRabbit

* **Documentation**
* Updated the site description and homepage messaging to position Commit
Check as policy-as-code for teams and AI agents.
* The messaging now highlights standards for commit messages, branch
names, authors, and sign-offs, enforced through hooks, CI, and pull
requests. It retains the existing details about validation and
reporting.

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

Co-authored-by: Xianpeng Shen <3353385+shenxianpeng@users.noreply.github.com>

Author: shenxianpeng

docs/index.md

@@ -5,7 +5,7 @@ hide:
 template: landing.html
 title: Commit Check
 seo_title: Commit Check — Commit message & branch name linter for Git
-description: Catch bad commits before they merge. Messages, branches, authors and AI attribution, checked from your commit hook to every pull request.
+description: Commit policy as code for teams and AI agents. Messages, branches, authors and AI attribution, checked from your commit hook to every pull request.
 ---
 
 <!-- markdownlint-disable MD041 MD033 MD036 MD025 -->
@@ -32,7 +32,7 @@ description: Catch bad commits before they merge. Messages, branches, authors an
 <div class="cc-hero__copy">
 <p class="cc-pill"><span class="cc-pill__dot"></span>Open source · MIT licensed</p>
 <h1 id="cc-title" class="cc-display">Catch bad commits <span class="cc-accent">before they merge.</span></h1>
-<p class="cc-lede">Commit Check validates commit messages, branch names, authors and sign-offs against one <code>cchk.toml</code> — in your commit hook, in CI, on every pull request and inside your AI agent. When the fix is obvious, it hands you the line.</p>
+<p class="cc-lede"><strong>Commit policy as code for teams and AI agents.</strong> Commit Check validates commit messages, branch names, authors and sign-offs against one <code>cchk.toml</code> — in your commit hook, in CI, on every pull request and inside your AI agent. When the fix is obvious, it hands you the line.</p>
 <div class="cc-actions">
 <a class="cc-btn cc-btn--primary" href="guides/github-actions/">Add to GitHub Actions <svg viewBox="0 0 16 16" aria-hidden="true"><path d="M3 8h9M8.5 4l4 4-4 4" fill="none" stroke="currentColor" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"/></svg></a>
 <div class="cc-install"><span class="cc-install__sigil" aria-hidden="true">$</span><code>pip install commit-check</code><button class="cc-copy" type="button" data-copy="pip install commit-check" aria-label="Copy the install command"><svg viewBox="0 0 16 16" aria-hidden="true"><rect x="5" y="5" width="8.5" height="8.5" rx="2" fill="none" stroke="currentColor" stroke-width="1.4"/><path d="M10.5 3.2A1.5 1.5 0 0 0 9 2H4a2 2 0 0 0-2 2v5a1.5 1.5 0 0 0 1.2 1.5" fill="none" stroke="currentColor" stroke-width="1.4"/></svg></button></div>

mkdocs.yml

@@ -3,8 +3,9 @@ site_name: Commit Check
 # netlify.toml.
 site_url: !ENV [SITE_URL, 'https://commit-check.com/']
 site_description: >-
-  Enforce commit message, branch naming, author and signoff standards —
-  one config file, across your CLI, pre-commit hooks, CI, and AI agents.
+  Commit policy as code for teams and AI agents: commit message, branch
+  naming, author and sign-off standards in one config file, enforced in
+  hooks, CI and pull requests.
 site_author: shenxianpeng
 copyright: Copyright © 2022 - 2026 Commit Check