Add index page to the sidebar when it's the only page

Automatically include the index page in the documentation sidebar when it is the only page present. This ensures the sidebar is not empty for a single-page documentation site, providing a more user-friendly experience.

packages/framework/src/Framework/Features/Navigation/DocumentationSidebar.php

@@ -22,6 +22,11 @@ protected function generate(): void
                 $this->items->put($route->getRouteKey(), NavItem::fromRoute($route));
             }
         });
+
+        // If there are no pages other than the index page, we add it to the sidebar so that it's not empty
+        if ($this->items->count() === 0 && DocumentationPage::home() !== null) {
+            $this->items->push(NavItem::fromRoute(DocumentationPage::home()));
+        }
     }
 
     public function hasGroups(): bool

packages/framework/tests/Feature/Services/DocumentationSidebarTest.php

@@ -376,6 +376,31 @@ public function test_is_group_active_for_index_page_with_no_groups()
         $this->assertFalse(DocumentationSidebar::create()->isGroupActive('foo'));
     }
 
+    public function test_index_page_added_to_sidebar_when_it_is_the_only_page()
+    {
+        Filesystem::touch('_docs/index.md');
+        $sidebar = DocumentationSidebar::create();
+
+        $this->assertCount(1, $sidebar->items);
+        $this->assertEquals(
+            collect([NavItem::fromRoute(Routes::get('docs/index'))]),
+            $sidebar->items
+        );
+    }
+
+    public function test_index_page_not_added_to_sidebar_when_other_pages_exist()
+    {
+        $this->createTestFiles(1);
+        Filesystem::touch('_docs/index.md');
+        $sidebar = DocumentationSidebar::create();
+
+        $this->assertCount(1, $sidebar->items);
+        $this->assertEquals(
+            collect([NavItem::fromRoute(Routes::get('docs/test-0'))]),
+            $sidebar->items
+        );
+    }
+
     protected function createTestFiles(int $count = 5): void
     {
         for ($i = 0; $i < $count; $i++) {