feat: add stdlib and browser examples

- stdlib/html.lux: Type-safe HTML construction
- stdlib/browser.lux: Browser utilities
- examples/web/: Counter app with DOM manipulation
- examples/counter.lux: Simple counter example

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

examples/web/serve.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Simple HTTP server for testing Lux web examples
+# Usage: ./serve.sh [port]
+
+PORT=${1:-8080}
+DIR="$(dirname "$0")"
+
+echo "Serving Lux web examples at http://localhost:$PORT"
+echo "Open http://localhost:$PORT/index.html in your browser"
+echo "Press Ctrl+C to stop"
+echo ""
+
+cd "$DIR"
+
+# Try python3 first, then python, then node
+if command -v python3 &> /dev/null; then
+    python3 -m http.server $PORT
+elif command -v python &> /dev/null; then
+    python -m SimpleHTTPServer $PORT
+elif command -v npx &> /dev/null; then
+    npx serve -p $PORT .
+else
+    echo "Error: No suitable HTTP server found."
+    echo "Install Python or Node.js to serve files."
+    exit 1
+fi