Add LLM endpoints, web frontend, and rate limiting config

- Added OpenAI-compatible LLM endpoints to API backend - Introduced web
frontend with Jinja2 templates and static assets - Implemented API proxy
routes in web service - Added sample db.json data for items, users,
orders, reviews, categories, llm_requests - Updated ADC and Helm configs
for separate AI and standard rate limiting - Upgraded FastAPI, Uvicorn,
and added httpx, Jinja2, python-multipart dependencies - Added API
configuration modal and client-side JS for web app

web/templates/items.html

@@ -0,0 +1,55 @@
+{% extends "base.html" %}
+
+{% block title %}Items - API Demo{% endblock %}
+
+{% block content %}
+<div class="page-header">
+    <h1>📦 Items Catalog</h1>
+    <p>Browse all available products</p>
+</div>
+
+<div id="items-container" class="items-grid">
+    <div class="loading">Loading items...</div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+const API_BASE = '/api';
+
+async function loadItems() {
+    try {
+        const response = await fetch(`${API_BASE}/items`);
+        const items = await response.json();
+
+        const container = document.getElementById('items-container');
+        container.innerHTML = items.map(item => `
+            <div class="item-card ${!item.in_stock ? 'out-of-stock' : ''}">
+                <div class="item-header">
+                    <h3>${item.name}</h3>
+                    <span class="badge ${item.in_stock ? 'badge-success' : 'badge-danger'}">
+                        ${item.in_stock ? 'In Stock' : 'Out of Stock'}
+                    </span>
+                </div>
+                <p class="item-description">${item.description || 'No description'}</p>
+                <div class="item-footer">
+                    <span class="price">$${item.price.toFixed(2)}</span>
+                    <button class="btn btn-sm" onclick="viewItem(${item.id})">View Details</button>
+                </div>
+            </div>
+        `).join('');
+    } catch (error) {
+        console.error('Error loading items:', error);
+        document.getElementById('items-container').innerHTML =
+            '<div class="error">Failed to load items. Please try again.</div>';
+    }
+}
+
+function viewItem(id) {
+    alert(`View item details for ID: ${id}\n\nAPI Endpoint: /api/items/${id}`);
+}
+
+// Load items on page load
+loadItems();
+</script>
+{% endblock %}