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/index.html

@@ -0,0 +1,86 @@
+{% extends "base.html" %}
+
+{% block title %}Home - API Demo{% endblock %}
+
+{% block content %}
+<div class="hero">
+    <h1>Welcome to API7EE Demo Platform</h1>
+    <p class="subtitle">Explore our API services with real-time data and AI-powered features</p>
+</div>
+
+<div class="cards-grid">
+    <div class="card">
+        <div class="card-icon">📦</div>
+        <h3>Items Management</h3>
+        <p>Browse and manage products in our catalog</p>
+        <a href="/items" class="btn btn-primary">View Items</a>
+    </div>
+
+    <div class="card">
+        <div class="card-icon">👥</div>
+        <h3>Users</h3>
+        <p>Manage user accounts and profiles</p>
+        <a href="/users" class="btn btn-primary">View Users</a>
+    </div>
+
+    <div class="card">
+        <div class="card-icon">🤖</div>
+        <h3>AI Chat (LLM)</h3>
+        <p>Chat with our videogame expert AI assistant</p>
+        <a href="/llm" class="btn btn-primary">Start Chat</a>
+    </div>
+
+    <div class="card">
+        <div class="card-icon">📚</div>
+        <h3>API Documentation</h3>
+        <p>Explore our OpenAPI/Swagger documentation</p>
+        <a href="/api/docs" target="_blank" class="btn btn-primary">Open Docs</a>
+    </div>
+</div>
+
+<div class="info-section">
+    <h2>Features</h2>
+    <ul class="features-list">
+        <li>✅ RESTful API with FastAPI</li>
+        <li>✅ AI Rate Limiting (100 tokens/60s for LLM)</li>
+        <li>✅ Standard Rate Limiting (100 req/60s per IP)</li>
+        <li>✅ OpenAI-compatible LLM endpoint</li>
+        <li>✅ Real-time data management</li>
+        <li>✅ Swagger/OpenAPI documentation</li>
+    </ul>
+</div>
+
+<div class="stats">
+    <div class="stat-box">
+        <h3 id="items-count">-</h3>
+        <p>Total Items</p>
+    </div>
+    <div class="stat-box">
+        <h3 id="users-count">-</h3>
+        <p>Active Users</p>
+    </div>
+    <div class="stat-box">
+        <h3>AI Ready</h3>
+        <p>LLM Service</p>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+// Fetch stats from API
+fetch('/api/items')
+    .then(res => res.json())
+    .then(data => {
+        document.getElementById('items-count').textContent = data.length;
+    })
+    .catch(err => console.error('Error fetching items:', err));
+
+fetch('/api/users')
+    .then(res => res.json())
+    .then(data => {
+        document.getElementById('users-count').textContent = data.length;
+    })
+    .catch(err => console.error('Error fetching users:', err));
+</script>
+{% endblock %}