feat: ticket views, statuses, participants, merge; mobile layout fixes (#5)

- New migrations: ticket views, statuses, participants, merge support
- New models: TicketView, TicketStatus, TicketParticipant
- New seeder: EmailTemplatesSeeder
- Console commands for ticketing
- Mobile: sidebar min-w-0/overflow-hidden, tab nav overflow-x-auto

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Models/PriorityLevel.php

@@ -3,19 +3,13 @@
 namespace Dashboard\Ticketing\Models;
 
 use Illuminate\Database\Eloquent\Model;
-use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class PriorityLevel extends Model
 {
     protected $table = 'ticketing_priority_levels';
 
-    protected $fillable = ['group_id', 'name', 'color', 'description', 'sort_order'];
-
-    public function group(): BelongsTo
-    {
-        return $this->belongsTo(TicketingGroup::class, 'group_id');
-    }
+    protected $fillable = ['name', 'color', 'description', 'sort_order'];
 
     public function tickets(): HasMany
     {