Add organizer suspension: toggle, badge, block access, audit log

- User.isSuspended (nullable bool, null = not suspended)
- Admin: toggle suspend/reactivate button on organizers list
- SuspendedUserSubscriber: redirects suspended users to homepage with error
- Audit log: organizer_suspended / organizer_reactivated
- Badge 'Suspendu' (red) replaces offer badge when suspended

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

migrations/Version20260322130000.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260322130000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add is_suspended to user';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE "user" ADD COLUMN IF NOT EXISTS is_suspended BOOLEAN DEFAULT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE "user" DROP COLUMN IF EXISTS is_suspended');
+    }
+}