seo fixes

app/Models/Post.php

@@ -79,10 +79,22 @@ class Post extends Model
 
     protected function bodyHtml(): Attribute
     {
-        return Attribute::get(fn () => Str::markdown($this->body, [
-            'html_input' => 'strip',
-            'allow_unsafe_links' => false,
-        ]));
+        return Attribute::get(function () {
+            $html = Str::markdown($this->body, [
+                'html_input' => 'strip',
+                'allow_unsafe_links' => false,
+            ]);
+
+            // The page template already renders the post title as an <h1>. If the
+            // Markdown body also opens with a top-level heading repeating that
+            // title, drop it so the page doesn't ship two identical <h1>s.
+            return preg_replace_callback(
+                '/^\s*<h1>(.*?)<\/h1>/is',
+                fn ($matches) => trim(strip_tags($matches[1])) === trim($this->title) ? '' : $matches[0],
+                $html,
+                limit: 1
+            );
+        });
     }
 
     protected function excerptOrSummary(): Attribute