fix: resolve known issues and improve code standards

- Fix known bugs in user, plan, and server modules
- Standardize code formatting and structure
- Optimize database queries and model relationships
- Improve request validation and error handling
- Update admin controllers for better consistency

app/Models/Plugin.php

@@ -11,6 +11,10 @@ class Plugin extends Model
     protected $guarded = [
         'id',
         'created_at',
-        'updated_at'
+        'updated_at',
+    ];
+
+    protected $casts = [
+        'is_enabled' => 'boolean'
     ];
 }