Fix switchTab function scope for ES6 module compatibility

- Expose switchTab to window object so onclick handlers can access it
- Fixes "switchTab is not defined" error when using type="module"
- Module-scoped functions are not accessible from inline HTML onclick handlers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

templates/index.html

@@ -958,7 +958,8 @@
         // ========================================
         // Tab Switching
         // ========================================
-        function switchTab(tabName) {
+        // Expose switchTab globally so onclick handlers can access it
+        window.switchTab = function(tabName) {
             // Hide all tabs
             document.querySelectorAll('.tab-content').forEach(tab => {
                 tab.classList.remove('active');