feat: Add notification services for Email, Telegram, and WhatsApp

- Implement EmailNotifier for sending batch and test notifications via email.
- Implement TelegramNotifier for sending batch and test notifications via Telegram.
- Implement WahaNotifier for sending batch and test notifications via WhatsApp using WAHA API.
- Create migration for client_categories table and update clients table to include category_id.
- Create migration for notification_settings table to manage notification configurations.
- Add ClientCategorySeeder to populate default client categories.
- Create manifest.json for PWA support.
- Implement service worker (sw.js) for caching static assets and offline support.
- Add edit event view for modifying scheduled events.
- Create search results view for displaying search queries.
- Develop notification settings view for configuring notification channels and triggers.

app/Models/Client.php

@@ -7,6 +7,7 @@ namespace App\Models;
 use App\Enums\ClientStatus;
 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\SoftDeletes;
 
@@ -18,13 +19,20 @@ class Client extends Model
         'name', 'email', 'phone', 'company',
         'ig_handle', 'tiktok_handle', 'youtube_handle',
         'address_line1', 'address_line2', 'city', 'state', 'postal_code', 'country',
-        'status', 'notes', 'avatar',
+        'status', 'category_id', 'notes', 'avatar',
     ];
 
     protected $casts = [
         'status' => ClientStatus::class,
     ];
 
+    // ── Relationships ────────────────────────────────────────────
+
+    public function category(): BelongsTo
+    {
+        return $this->belongsTo(ClientCategory::class, 'category_id');
+    }
+
     public function events(): HasMany
     {
         return $this->hasMany(Event::class);
@@ -45,6 +53,8 @@ class Client extends Model
         return $this->hasMany(MediaFile::class);
     }
 
+    // ── Accessors ────────────────────────────────────────────────
+
     public function getFullAddressAttribute(): string
     {
         return collect([