feat: move profile completeness check from login to booking flow entry

- Add profileComplete flag to User entity to avoid API calls
- Set flag during login (BpnAuthenticator) and profile save
- Check flag in IndexController when entering booking flow
- Remove ProfileCompletionSubscriber (no longer needed)

Users with incomplete profiles are only redirected when starting
a new booking, not on every login. Eliminates extra API call by
caching completeness status on the user entity.

migrations/Version20260119174522.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20260119174522 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Add profile_complete flag to user table';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE user ADD profile_complete TINYINT(1) NOT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE user DROP profile_complete');
+    }
+}