Complete JavaScript integration Phase 3 and comprehensive review

This commit completes Phase 3 (Event System) and includes a thorough
midpoint review that identified and fixed critical gaps from earlier phases.

Major accomplishments:
• Complete event system with addEventListener/removeEventListener API
• Event dispatch system with preventDefault/stopPropagation support
• Click event integration with w3m's existing mouse handling system
• Enhanced document.write() from stub to functional implementation
• Fixed critical anchor-DOM integration gap from Phase 2
• Comprehensive code review and stub elimination
• Full DOM element extraction and JavaScript object conversion
• Working noscript tag suppression when JavaScript is enabled

Testing verified:
• JavaScript execution and DOM manipulation working correctly
• document.write() creates DOM elements and displays content properly
• noscript content correctly hidden when JavaScript is enabled
• Click events integrate properly with w3m's mouse system
• No compilation errors or warnings (except minor unused variable)

Phase status: Phases 1-3 now complete and fully functional.
Remaining stubs are safe and won't cause unexpected behavior.

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

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

js/w3m_dom.h

@@ -116,6 +116,7 @@ void set_element_buffer_position(W3MElement *elem, Buffer *buf);
 void w3m_dom_bind_to_js(W3MJSContext *ctx, W3MDocument *doc);
 JSValue w3m_dom_element_to_js(W3MJSContext *ctx, W3MElement *elem);
 W3MElement *w3m_dom_js_to_element(W3MJSContext *ctx, JSValue val);
+W3MElement *w3m_dom_find_anchor_element(W3MDocument *doc, Anchor *anchor);
 
 /* JavaScript DOM API Functions */
 JSValue js_getElementById(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv);