feat(tasks): complete task management system with Kanban, Calendar, notifications

- Add Task model with subtasks, priorities, status transitions, dates, hours
- Add Comment polymorphic model for tasks/issues/projects
- Livewire components: TaskManager (list+filters), TaskForm (modal), TaskDetail, TaskKanban (drag&drop), TaskCalendar (FullCalendar)
- TaskPolicy with permissions (view/create/edit/delete/assign/manage all)
- Notifications: assigned, status change, overdue, comment added
- Daily overdue notification job scheduled
- Dashboard widget unifies IssueTask + Task
- i18n: en/es/fr/ru (393 keys each)
- Routes, navigation, offline sync support
- 101 tests passing, Pint compliant on new files

app/Notifications/TaskStatusChangedNotification.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace App\Notifications;
+
+use App\Models\Task;
+use Illuminate\Bus\Queueable;
+use Illuminate\Notifications\Notification;
+
+class TaskStatusChangedNotification extends Notification
+{
+    use Queueable;
+
+    public function __construct(public Task $task, public string $oldStatus) {}
+
+    public function via($notifiable): array
+    {
+        return ['database'];
+    }
+
+    public function toArray($notifiable): array
+    {
+        $label = [
+            'pending' => 'pendiente',
+            'in_progress' => 'en progreso',
+            'completed' => 'completada',
+            'cancelled' => 'cancelada',
+        ][$this->task->status] ?? $this->task->status;
+
+        $oldLabel = [
+            'pending' => 'pendiente',
+            'in_progress' => 'en progreso',
+            'completed' => 'completada',
+            'cancelled' => 'cancelada',
+        ][$this->oldStatus] ?? $this->oldStatus;
+
+        return [
+            'type' => 'task_status_changed',
+            'task_id' => $this->task->id,
+            'project_id' => $this->task->project_id,
+            'old_status' => $this->oldStatus,
+            'new_status' => $this->task->status,
+            'message' => "La tarea '{$this->task->title}' cambió de {$oldLabel} a {$label}",
+        ];
+    }
+}