chore: add php-cs-fixer with PSR-12 config and CI check

- Add friendsofphp/php-cs-fixer to require-dev
- Create .php-cs-fixer.dist.php configured for @PSR12 ruleset
- Add php-cs-fixer dry-run step to CI pipeline
- Auto-fix existing PSR-12 violations
- Document code style tooling in readme.md

tests/Unit/Command/GenerateBackupCodesCommandTest.php

@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace App\Tests\Unit\Command;
@@ -10,25 +11,29 @@ use PHPUnit\Framework\TestCase;
 use Symfony\Component\Cache\Adapter\ArrayAdapter;
 use Symfony\Component\Console\Tester\CommandTester;
 
-final class GenerateBackupCodesCommandTest extends TestCase {
-
+final class GenerateBackupCodesCommandTest extends TestCase
+{
     /** PersistCache is final, so construct a real one backed by ArrayAdapters. */
-    private function makePersistCache(): PersistCache {
+    private function makePersistCache(): PersistCache
+    {
         return new PersistCache(new ArrayAdapter(), new ArrayAdapter());
     }
 
     /** A stub BackupCodeInterface that returns the given codes from generate(). */
-    private function makeManagerStub(array $generatedCodes): BackupCodeInterface {
+    private function makeManagerStub(array $generatedCodes): BackupCodeInterface
+    {
         $manager = $this->createStub(BackupCodeInterface::class);
         $manager->method('generate')->willReturn($generatedCodes);
         return $manager;
     }
 
-    public function testGenerateDefaultCountOutputsCodes(): void {
+    public function testGenerateDefaultCountOutputsCodes(): void
+    {
         $codes = ['abc123', 'def456', 'ghi789', 'jkl012', 'mno345',
                   'pqr678', 'stu901', 'vwx234', 'yzA567', 'bCd890'];
         $command = new GenerateBackupCodesCommand(
-            $this->makeManagerStub($codes), $this->makePersistCache()
+            $this->makeManagerStub($codes),
+            $this->makePersistCache()
         );
         $command->setName('app:generate-backup-codes');
 
@@ -42,7 +47,8 @@ final class GenerateBackupCodesCommandTest extends TestCase {
         }
     }
 
-    public function testGenerateSpecificCountPassesCountToManager(): void {
+    public function testGenerateSpecificCountPassesCountToManager(): void
+    {
         $manager = $this->createMock(BackupCodeInterface::class);
         $manager->expects(self::once())
             ->method('generate')
@@ -58,7 +64,8 @@ final class GenerateBackupCodesCommandTest extends TestCase {
         self::assertSame(0, $exit);
     }
 
-    public function testDefaultCountArgumentIsTen(): void {
+    public function testDefaultCountArgumentIsTen(): void
+    {
         // the configured default for the count argument should be 10
         $manager = $this->createMock(BackupCodeInterface::class);
         $manager->expects(self::once())
@@ -76,13 +83,15 @@ final class GenerateBackupCodesCommandTest extends TestCase {
         $this->addToAssertionCount(1);
     }
 
-    public function testBootsAndPersistsCache(): void {
+    public function testBootsAndPersistsCache(): void
+    {
         // PersistCache is final and can't be mocked, but we can verify the
         // command runs end-to-end with a real instance; boot()/persist()
         // are invoked implicitly. A successful exit confirms both were called
         // without throwing.
         $command = new GenerateBackupCodesCommand(
-            $this->makeManagerStub(['code1']), $this->makePersistCache()
+            $this->makeManagerStub(['code1']),
+            $this->makePersistCache()
         );
         $command->setName('app:generate-backup-codes');
 
@@ -92,9 +101,11 @@ final class GenerateBackupCodesCommandTest extends TestCase {
         self::assertSame(0, $exit);
     }
 
-    public function testZeroCodesOutputsNothing(): void {
+    public function testZeroCodesOutputsNothing(): void
+    {
         $command = new GenerateBackupCodesCommand(
-            $this->makeManagerStub([]), $this->makePersistCache()
+            $this->makeManagerStub([]),
+            $this->makePersistCache()
         );
         $command->setName('app:generate-backup-codes');
 
@@ -105,9 +116,11 @@ final class GenerateBackupCodesCommandTest extends TestCase {
         self::assertSame('', trim($tester->getDisplay()));
     }
 
-    public function testCommandNameAndDescriptionAreConfigured(): void {
+    public function testCommandNameAndDescriptionAreConfigured(): void
+    {
         $command = new GenerateBackupCodesCommand(
-            $this->makeManagerStub([]), $this->makePersistCache()
+            $this->makeManagerStub([]),
+            $this->makePersistCache()
         );
         // configuring via the Application runs the protected configure()
         $app = new \Symfony\Component\Console\Application();