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.

src/Entity/User.php

@@ -35,6 +35,9 @@ class User implements UserInterface, PasswordAuthenticatedUserInterface
     #[ORM\Column(type: 'datetime_immutable', nullable: true)]
     private ?\DateTimeImmutable $lastLoginAt = null;
 
+    #[ORM\Column(type: 'boolean')]
+    private bool $profileComplete = false;
+
     public function __construct(string $email)
     {
         $this->email = $email;
@@ -129,6 +132,18 @@ class User implements UserInterface, PasswordAuthenticatedUserInterface
         return $this;
     }
 
+    public function isProfileComplete(): bool
+    {
+        return $this->profileComplete;
+    }
+
+    public function setProfileComplete(bool $profileComplete): static
+    {
+        $this->profileComplete = $profileComplete;
+
+        return $this;
+    }
+
     public function eraseCredentials(): void
     {
     }