feat(absences) : avancement module absences + suppression du portail client

Deux lots regroupés sur la branche feat/absence-management.

Suppression complète du portail client :
- retire ROLE_CLIENT (security.yaml) ; User::getRoles() ajoute toujours ROLE_USER
- supprime l'entité ClientTicket (+ repo, states, relations), User.client et
  User.allowedProjects, NotificationService, ProjectAllowedExtension, le bloc
  ROLE_CLIENT de MailAccessChecker
- front : pages /portal, layout portal, composants client-ticket/,
  AdminClientTicketTab, services/dto/i18n/docs associés
- fixtures : retire les users client-liot / client-acme
- migration Version20260522110000 (drop client_ticket, user_allowed_projects,
  colonnes liées ; task_document.task_id -> NOT NULL)
- tests : retire les cas obsolètes testant le blocage des clients sur le mail

Module gestion des absences (WIP) :
- entités / migrations (Version20260521160000, Version20260522090000)
- pages absences.vue / team-absences.vue, composants frontend/components/absence/
- services front, AccrueLeaveCommand, PublicHolidayController

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

src/Entity/Task.php

@@ -124,11 +124,6 @@ class Task
     #[Groups(['task:read'])]
     private Collection $documents;
 
-    #[ORM\ManyToOne(targetEntity: ClientTicket::class)]
-    #[ORM\JoinColumn(nullable: true, onDelete: 'SET NULL')]
-    #[Groups(['task:read', 'task:write'])]
-    private ?ClientTicket $clientTicket = null;
-
     #[ORM\Column(type: 'datetime_immutable', nullable: true)]
     #[Groups(['task:read', 'task:write'])]
     private ?DateTimeImmutable $scheduledStart = null;
@@ -342,18 +337,6 @@ class Task
         return $this->documents;
     }
 
-    public function getClientTicket(): ?ClientTicket
-    {
-        return $this->clientTicket;
-    }
-
-    public function setClientTicket(?ClientTicket $clientTicket): static
-    {
-        $this->clientTicket = $clientTicket;
-
-        return $this;
-    }
-
     public function getScheduledStart(): ?DateTimeImmutable
     {
         return $this->scheduledStart;