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

Dockerfile.docs

@@ -1,17 +1,6 @@
-FROM node:20-alpine AS builder
-
-WORKDIR /app/docs
-
-COPY docs/package*.json ./
-RUN npm install
-
-COPY docs ./
-RUN npm run build
-
 FROM nginx:alpine
 
-COPY --from=builder /app/docs/dist /usr/share/nginx/html
-COPY docs/nginx.conf /etc/nginx/http.d/default.conf
+COPY www/ /usr/share/nginx/html/
 
 EXPOSE 80