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/Models/Comment.php

@@ -0,0 +1,101 @@
+<?php
+
+namespace App\Models;
+
+use App\Notifications\TaskCommentNotification;
+use App\Traits\LogsActivity;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+
+class Comment extends Model
+{
+    use HasFactory, LogsActivity;
+
+    protected $fillable = [
+        'commentable_type',
+        'commentable_id',
+        'user_id',
+        'body',
+        'parent_id',
+    ];
+
+    protected $casts = [
+        'body' => 'string',
+    ];
+
+    // ============================================================
+    // Events / Observers
+    // ============================================================
+
+    protected static function booted(): void
+    {
+        static::created(function (Comment $comment) {
+            // Notify if comment is on a Task
+            if ($comment->commentable_type === Task::class) {
+                $task = $comment->commentable;
+                if ($task) {
+                    // Notify creator and assignee (except the commenter)
+                    $usersToNotify = collect([$task->creator, $task->assignee])
+                        ->unique('id')
+                        ->filter(fn ($u) => $u && $u->id !== $comment->user_id);
+
+                    foreach ($usersToNotify as $user) {
+                        $user->notify(new TaskCommentNotification($task, $comment));
+                    }
+                }
+            }
+        });
+    }
+
+    // ============================================================
+    // Relationships
+    // ============================================================
+
+    public function commentable(): MorphTo
+    {
+        return $this->morphTo();
+    }
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function parent(): BelongsTo
+    {
+        return $this->belongsTo(Comment::class, 'parent_id');
+    }
+
+    public function replies(): HasMany
+    {
+        return $this->hasMany(Comment::class, 'parent_id')->orderBy('created_at');
+    }
+
+    // ============================================================
+    // Scopes
+    // ============================================================
+
+    public function scopeTopLevel($query)
+    {
+        return $query->whereNull('parent_id');
+    }
+
+    public function scopeWithReplies($query)
+    {
+        return $query->with('replies.user');
+    }
+
+    // ============================================================
+    // Accessors
+    // ============================================================
+
+    public function getExcerptAttribute(): string
+    {
+        return strlen($this->body) > 150
+            ? substr($this->body, 0, 150).'...'
+            : $this->body;
+    }
+}