Restructure API documentation pages to use standard container layout

- Moved API documentation content inside standard container div like dashboard/history pages
- Updated header styling to work within container (rounded corners, padding, shadow)
- Maintained modern design while following consistent page layout patterns

templates/admin_api.html

@@ -7,9 +7,10 @@
 .api-header {
     background: linear-gradient(135deg, #dc2626 0%, #b91c1c 100%);
     color: white;
-    padding: 3rem 0;
-    margin-top: -1rem;
+    padding: 2rem;
+    border-radius: 12px;
     margin-bottom: 2rem;
+    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
 }
 
 .api-header h1 {
@@ -177,14 +178,11 @@
 {% endblock %}
 
 {% block content %}
-<div class="api-header">
-    <div class="container">
+<div class="container">
+    <div class="api-header">
         <h1><i class="fas fa-crown"></i> Admin API Documentation</h1>
         <p class="lead">Administrative API endpoints for system management</p>
     </div>
-</div>
-
-<div class="container">
     <div class="auth-notice">
         <div class="d-flex align-items-start">
             <i class="fas fa-exclamation-triangle alert-icon"></i>

templates/api.html

@@ -7,9 +7,10 @@
 .api-header {
     background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
     color: white;
-    padding: 3rem 0;
-    margin-top: -1rem;
+    padding: 2rem;
+    border-radius: 12px;
     margin-bottom: 2rem;
+    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
 }
 
 .api-header h1 {
@@ -177,14 +178,11 @@
 {% endblock %}
 
 {% block content %}
-<div class="api-header">
-    <div class="container">
+<div class="container">
+    <div class="api-header">
         <h1><i class="fas fa-code"></i> API Documentation</h1>
         <p class="lead">Programmatic access to Video AI functionality</p>
     </div>
-</div>
-
-<div class="container">
     <div class="auth-notice">
         <div class="d-flex align-items-start">
             <i class="fas fa-shield-alt alert-icon"></i>