inform users about maintenance mode and syde/phpcs

Author: tfrommen

Diff for: README.md

@@ -6,6 +6,11 @@
 
 ---
 
+> [!IMPORTANT]
+> Development on this package has shifted to maintenance mode. We remain committed to fixing bugs, ensuring compatibility, and addressing security concerns, but new features are not planned at this time. For active projects, we recommend migrating to [`syde/phpcs`](https://github.com/inpsyde/phpcs), the next-generation Syde PHP Coding Standards, supporting PHP 8.1+.
+
+---
+
 # Usage
 
 When the package is installed via Composer, and dependencies are updated, everything is ready and 

Diff for: composer.json

@@ -80,5 +80,8 @@
             "composer/*": true,
             "dealerdirect/phpcodesniffer-composer-installer": true
         }
+    },
+    "suggest": {
+        "syde/phpcs": "The next-generation Syde PHP Coding Standards for WordPress development at scale, supporting PHP 8.1+."
     }
 }