feat(docs): enhance documentation UI with ToC and GitHub stats

Add new features to documentation UI:
- Add table of contents with scroll spy functionality
- Add GitHub repository statistics badge
- Implement new centered layout system with fixed sidebar
- Add conditional Playwright installation based on CRAWL4AI_MODE

Breaking changes: None

docs/md_v2/assets/styles.css

@@ -50,8 +50,17 @@
     --display-h1-decoration: none;
 
     --display-h1-decoration: none;
+
+    --header-height: 65px; /* Adjust based on your actual header height */
+    --sidebar-width: 280px; /* Adjust based on your desired sidebar width */
+    --toc-width: 240px; /* Adjust based on your desired ToC width */
+    --layout-transition-speed: 0.2s; /* For potential future animations */
+
+    --page-width : 90em; /* Adjust based on your design */
 }
 
+
+
 /* body {
     background-color: var(--background-color);
     color: var(--font-color);
@@ -256,4 +265,6 @@ div.badges a {
 }
 div.badges a > img {
     width: auto;
-}
+}
+
+