docs: add geo blocking docs and refresh screenshots

- Add Geo Blocking section to README with rule types and GeoIP setup
- Add Geo Blocking card to landing page (site/index.html)
- Refresh all 4 screenshots from current UI

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

site/index.html

@@ -54,7 +54,7 @@
     <section class="hero container">
       <h1>Control Every Edge.</h1>
       <p>The modern, secure context for your reverse proxy. Manage Caddy with an intuitive interface, automatic HTTPS,
-        and detailed audit logging.</p>
+        geo blocking, and detailed audit logging.</p>
 
       <div class="btn-group">
         <a href="#deployment" class="btn btn-primary">Get Started</a>
@@ -86,6 +86,10 @@
             out of the
             box.</p>
         </div>
+        <div class="card">
+          <h3>Geo Blocking</h3>
+          <p>Block or allow traffic by country, continent, ASN, CIDR range, or exact IP — per proxy host, with allow-override rules.</p>
+        </div>
         <div class="card">
           <h3>Access Control</h3>
           <p>Secure your endpoints with basic auth, IP access lists, or valid OAuth2/OIDC sessions.</p>