Refactor admin/user isolation logic and model methods

Moved admin/user isolation checks and related methods from Domain and NotificationGroup models to User model for better separation of concerns. Replaced direct database queries in controllers and services with new model methods. Added methods for assigning unassigned domains/groups, searching domains, and clearing old notification logs. Updated views for improved UI consistency.

app/Models/User.php

@@ -284,5 +284,58 @@ class User extends Model
         $user = $this->find($userId);
         return $user && $user['email_verified'];
     }
+
+    /**
+     * Check if user is admin
+     */
+    public function isAdmin(?int $userId): bool
+    {
+        if (!$userId) {
+            return false;
+        }
+        
+        $stmt = $this->db->prepare("SELECT role FROM users WHERE id = ?");
+        $stmt->execute([$userId]);
+        $user = $stmt->fetch();
+        return $user && $user['role'] === 'admin';
+    }
+
+    /**
+     * Get first admin user
+     */
+    public function getFirstAdminUser(): ?array
+    {
+        $stmt = $this->db->query("SELECT * FROM users WHERE role = 'admin' ORDER BY id ASC LIMIT 1");
+        return $stmt->fetch() ?: null;
+    }
+
+    /**
+     * Get all admin users
+     */
+    public function getAllAdmins(): array
+    {
+        return $this->where('role', 'admin');
+    }
+
+    /**
+     * Count admin users
+     */
+    public function countAdmins(): int
+    {
+        $stmt = $this->db->query("SELECT COUNT(*) as count FROM users WHERE role = 'admin'");
+        $result = $stmt->fetch();
+        return (int)$result['count'];
+    }
+
+    /**
+     * Find user by verification token (debug version - includes all users regardless of verification status)
+     */
+    public function findByVerificationTokenDebug(string $token): ?array
+    {
+        $stmt = $this->db->prepare("SELECT id, email, email_verified, email_verification_token FROM users WHERE email_verification_token = ?");
+        $stmt->execute([$token]);
+        $result = $stmt->fetch();
+        return $result ?: null;
+    }
 }