Fix notification preferences 500 error — match actual DB schema

The component was querying a non-existent 'channels' JSON column.
The table uses separate boolean columns: channel_email, channel_sms, channel_in_app.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Livewire/Profile/NotificationPreferences.php

@@ -30,12 +30,20 @@ public function mount(): void
 
         $existing = DB::table('notification_preferences')
             ->where('user_id', $userId)
-            ->pluck('channels', 'event_type')
-            ->toArray();
+            ->get()
+            ->keyBy('event_type');
 
         foreach ($this->eventTypes as $type => $label) {
-            $channels = isset($existing[$type]) ? json_decode($existing[$type], true) : ['email' => true, 'sms' => true, 'in_app' => true];
-            $this->preferences[$type] = $channels;
+            if (isset($existing[$type])) {
+                $row = $existing[$type];
+                $this->preferences[$type] = [
+                    'email' => (bool) $row->channel_email,
+                    'sms' => (bool) $row->channel_sms,
+                    'in_app' => (bool) $row->channel_in_app,
+                ];
+            } else {
+                $this->preferences[$type] = ['email' => true, 'sms' => true, 'in_app' => true];
+            }
         }
     }
 
@@ -47,7 +55,12 @@ public function save(): void
             DB::table('notification_preferences')
                 ->updateOrInsert(
                     ['user_id' => $userId, 'event_type' => $eventType],
-                    ['channels' => json_encode($channels), 'updated_at' => now()]
+                    [
+                        'channel_email' => $channels['email'] ?? true,
+                        'channel_sms' => $channels['sms'] ?? true,
+                        'channel_in_app' => true,
+                        'updated_at' => now(),
+                    ]
                 );
         }