feat: replace Starlight docs with simple HTML product website

- Removed docs/ (Starlight)
- Added www/ with pure HTML/CSS/JS landing page
- Product website with features, how it works, get started
- Basic HTML documentation pages (installation, quick start, AI providers)
- Dockerfile.docs now serves static files from www/
- Updated README and AGENTS.md

www/js/main.js

@@ -0,0 +1,21 @@
+document.addEventListener('DOMContentLoaded', () => {
+  const navbar = document.querySelector('.navbar');
+  
+  window.addEventListener('scroll', () => {
+    if (window.scrollY > 50) {
+      navbar.style.background = 'rgba(15, 23, 42, 0.98)';
+    } else {
+      navbar.style.background = 'rgba(15, 23, 42, 0.9)';
+    }
+  });
+
+  document.querySelectorAll('a[href^="#"]').forEach(anchor => {
+    anchor.addEventListener('click', function (e) {
+      e.preventDefault();
+      const target = document.querySelector(this.getAttribute('href'));
+      if (target) {
+        target.scrollIntoView({ behavior: 'smooth', block: 'start' });
+      }
+    });
+  });
+});