feat: Implement UI components for Django templates

- Added Button component with various styles and sizes.
- Introduced Card component for displaying content with titles and descriptions.
- Created Input component for form fields with support for various attributes.
- Developed Toast Notification Container for displaying alerts and messages.
- Designed pages for listing designers and operators with pagination and responsive layout.
- Documented frontend migration from React to HTMX + Alpine.js, detailing component usage and integration.

backend/templates/components/ui/card.html

@@ -0,0 +1,37 @@
+{% comment %}
+Card Component - Django Template Version of shadcn/ui Card
+Usage: {% include 'components/ui/card.html' with title='Card Title' content='Card content' %}
+{% endcomment %}
+
+<div class="rounded-lg border bg-card text-card-foreground shadow-sm {{ class|default:'' }}">
+  {% if title or header_content %}
+  <div class="flex flex-col space-y-1.5 p-6">
+    {% if title %}
+    <h3 class="text-2xl font-semibold leading-none tracking-tight">{{ title }}</h3>
+    {% endif %}
+    {% if description %}
+    <p class="text-sm text-muted-foreground">{{ description }}</p>
+    {% endif %}
+    {% if header_content %}
+    {{ header_content|safe }}
+    {% endif %}
+  </div>
+  {% endif %}
+  
+  {% if content or body_content %}
+  <div class="p-6 pt-0">
+    {% if content %}
+    {{ content|safe }}
+    {% endif %}
+    {% if body_content %}
+    {{ body_content|safe }}
+    {% endif %}
+  </div>
+  {% endif %}
+  
+  {% if footer_content %}
+  <div class="flex items-center p-6 pt-0">
+    {{ footer_content|safe }}
+  </div>
+  {% endif %}
+</div>