added logo theme to zitinexus

UI/public/assets/css/style.css

@@ -204,10 +204,38 @@ body {
     margin: 0 auto;
 }
 
+.header-brand {
+    display: flex;
+    align-items: center;
+    gap: 1rem;
+}
+
+.logo {
+    width: 40px;
+    height: 40px;
+    background-color: var(--primary-color);
+    border-radius: 8px;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: white;
+    font-size: 1.25rem;
+    font-weight: 700;
+    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+    box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
+    transition: all 0.2s ease;
+}
+
+.logo:hover {
+    transform: translateY(-1px);
+    box-shadow: 0 4px 8px rgba(37, 99, 235, 0.3);
+}
+
 .header-title {
     font-size: 1.5rem;
     font-weight: 700;
     color: var(--text-primary);
+    margin: 0;
 }
 
 .header-actions {

UI/public/dashboard.php

@@ -97,7 +97,10 @@ $systemStatus = $enrollmentManager->getSystemStatus();
         <!-- Header -->
         <header class="header">
             <div class="header-content">
+                <div class="header-brand">
+                    <div class="logo">Z</div>
                     <h1 class="header-title"><?php echo APP_NAME; ?></h1>
+                </div>
                 <div class="header-actions">
                     <div class="user-info">
                         Welcome, <strong><?php echo htmlspecialchars($currentUser['username']); ?></strong>

UI/public/index.php

@@ -55,6 +55,7 @@ if (isset($loginError)) {
     <div class="login-container">
         <div class="login-card">
             <div class="login-header">
+                <div class="logo" style="margin: 0 auto 1rem auto;">Z</div>
                 <h1><?php echo APP_NAME; ?></h1>
                 <p>Router Enrollment Management Interface</p>
                 <p class="text-sm text-secondary">Version <?php echo APP_VERSION; ?></p>

UI/public/setup.php

@@ -58,6 +58,7 @@ $currentUser = AuthManager::getCurrentUser();
     <div class="login-container">
         <div class="login-card" style="max-width: 500px;">
             <div class="login-header">
+                <div class="logo" style="margin: 0 auto 1rem auto;">Z</div>
                 <h1>🔐 Security Setup Required</h1>
                 <p>For security reasons, you must change the default credentials before proceeding.</p>
             </div>