docs: add ECSConfig extension examples to documentation

- Add 'Extending ECS Configuration' section to overriding-defaults.rst
- Add FAQ entry explaining how to extend ECS configuration

Refs: #6

Author: coisa

docs/configuration/overriding-defaults.rst

@@ -51,6 +51,31 @@ To customize Rector for one library, create ``rector.php`` in the consumer
 project root. The ``refactor`` command and the Rector phase inside ``phpdoc``
 will use that file instead of the packaged default.
 
+Extending ECS Configuration
+----------------------------
+
+Instead of copying the entire ``ecs.php`` file, consumers can extend the
+default configuration using the ``ECSConfig`` class:
+
+.. code-block:: php
+
+   <?php
+
+   use FastForward\DevTools\Config\ECSConfig;
+   use PhpCsFixer\Fixer\Phpdoc\PhpdocAlignFixer;
+
+   $config = ECSConfig::configure();
+   $config->withRules([CustomRule::class]);
+   $config->withConfiguredRule(PhpdocAlignFixer::class, ['align' => 'right']);
+
+   return $config;
+
+This approach:
+
+- Eliminates duplication of the base configuration
+- Automatically receives upstream updates
+- Only requires overriding what is needed
+
 What Is Not Overwritten Automatically
 -------------------------------------
 

docs/faq.rst

@@ -76,6 +76,24 @@ Create only the local configuration file you want to customize, such as
 ``rector.php`` or ``phpunit.xml``. DevTools will prefer that file and keep the
 rest on the packaged defaults.
 
+How do I extend the ECS configuration without copying the whole file?
+----------------------------------------------------------------------
+
+Use the ``ECSConfig`` class to extend instead of replace:
+
+.. code-block:: php
+
+   <?php
+
+   use FastForward\DevTools\Config\ECSConfig;
+
+   $config = ECSConfig::configure();
+   $config->withRules([CustomRule::class]);
+
+   return $config;
+
+This approach automatically receives upstream updates while allowing additive customization.
+
 Can I generate coverage without running the full ``standards`` pipeline?
 ------------------------------------------------------------------------
 

src/Config/ECSConfig.php

@@ -53,7 +53,6 @@ final class ECSConfig
     public static function configure(): ECSConfigBuilder
     {
         $cwd = getcwd();
-
         $config = new ECSConfigBuilder();
 
         return $config