Add abstract getMaxVarcharLength() to Adapter class

Add the abstract method to the base Adapter class and implement
it in the Pool adapter to fix PHPStan errors.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: abnegate

src/Database/Adapter.php

@@ -899,6 +899,13 @@ abstract public function getLimitForIndexes(): int;
      */
     abstract public function getMaxIndexLength(): int;
 
+    /**
+     * Get the maximum VARCHAR length for this adapter
+     *
+     * @return int
+     */
+    abstract public function getMaxVarcharLength(): int;
+
     /**
      * Get the maximum UID length for this adapter
      *

src/Database/Adapter/Pool.php

@@ -287,6 +287,11 @@ public function getMaxIndexLength(): int
         return $this->delegate(__FUNCTION__, \func_get_args());
     }
 
+    public function getMaxVarcharLength(): int
+    {
+        return $this->delegate(__FUNCTION__, \func_get_args());
+    }
+
     public function getMaxUIDLength(): int
     {
         return $this->delegate(__FUNCTION__, \func_get_args());