Init Astro site with Docker and AI workflows

- Add landing page and base layout with cozy theme
- Configure Astro, TypeScript, and project settings
- Add Dockerfile, Nginx config, and docker-compose
- Include favicon and site metadata
- Add documentation: README, DEVELOPMENT, PROJECT_CONTEXT, TODO, CLAUDE
- Add Gitea workflows for AI chat, PR review, issue triage, and codebase
  review

nginx.conf

@@ -0,0 +1,31 @@
+server {
+    listen 80;
+    server_name localhost;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Gzip compression
+    gzip on;
+    gzip_vary on;
+    gzip_min_length 1024;
+    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml+rss application/javascript application/json;
+
+    # Security headers
+    add_header X-Frame-Options "SAMEORIGIN" always;
+    add_header X-Content-Type-Options "nosniff" always;
+    add_header X-XSS-Protection "1; mode=block" always;
+
+    # Cache static assets
+    location ~* \.(jpg|jpeg|png|gif|ico|css|js|svg|woff|woff2|ttf|eot)$ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+
+    # Main location
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    # Custom error pages
+    error_page 404 /404.html;
+}