Redesign Symfony page with clean, professional styling

- Simplify table of contents navigation (remove colored icons)
- Remove gradient backgrounds from section headers
- Simplify version requirement cards (remove gradients and accent lines)
- Update callout boxes to use consistent slate-50 background
- Simplify notification type cards (remove gradient backgrounds)
- Use uniform slate/indigo color scheme throughout
- Fix malformed HTML in code blocks
- Update notification example to match callout style

docs/_data/manifest.json

@@ -1,5 +1,5 @@
 {
-  "dist/main.css": "/dist/main.2ef7930f.css",
+  "dist/main.css": "/dist/main.309ebc17.css",
   "dist/main.js": "/dist/main.943ce8e8.js",
   "dist/455.3a7b4474.css": "/dist/455.3a7b4474.css",
   "dist/455.095e6545.js": "/dist/455.095e6545.js",

docs/dist/entrypoints.json

@@ -2,7 +2,7 @@
   "entrypoints": {
     "main": {
       "css": [
-        "/dist/main.2ef7930f.css"
+        "/dist/main.309ebc17.css"
       ],
       "js": [
         "/dist/main.943ce8e8.js"