feat(mail) : MailSettings ApiResource singleton (GET/PATCH /api/mail/configuration)

- ApiResource MailSettings expose les operations Get + Patch sur /api/mail/configuration
- Provider + Processor relient le DTO a l'entite MailConfiguration (singleton)
- password en write-only (jamais retourne) + hasPassword en lecture
- chiffrement password via TokenEncryptor (sodium)
- securite ROLE_ADMIN sur les deux operations

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ApiResource/MailSettings.php

@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\ApiResource;
+
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Get;
+use ApiPlatform\Metadata\Patch;
+use App\State\Mail\MailSettingsProcessor;
+use App\State\Mail\MailSettingsProvider;
+use Symfony\Component\Serializer\Attribute\Groups;
+
+#[ApiResource(
+    operations: [
+        new Get(
+            uriTemplate: '/mail/configuration',
+            normalizationContext: ['groups' => ['mail_settings:read']],
+            provider: MailSettingsProvider::class,
+            security: "is_granted('ROLE_ADMIN')",
+        ),
+        new Patch(
+            uriTemplate: '/mail/configuration',
+            denormalizationContext: ['groups' => ['mail_settings:write']],
+            normalizationContext: ['groups' => ['mail_settings:read']],
+            provider: MailSettingsProvider::class,
+            processor: MailSettingsProcessor::class,
+            security: "is_granted('ROLE_ADMIN')",
+        ),
+    ],
+)]
+final class MailSettings
+{
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $protocol = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $imapHost = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?int $imapPort = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $imapEncryption = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $smtpHost = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?int $smtpPort = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $smtpEncryption = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $username = null;
+
+    #[Groups(['mail_settings:write'])]
+    public ?string $password = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public ?string $sentFolderPath = null;
+
+    #[Groups(['mail_settings:read', 'mail_settings:write'])]
+    public bool $enabled = false;
+
+    #[Groups(['mail_settings:read'])]
+    public bool $hasPassword = false;
+}