feat: add debugging tools (highlight, console, errors)

Adds three new browser automation tools for visual debugging and error tracking:

- browser_highlight: Visually highlight elements with colored borders and optional tag/ID info
- browser_console: Capture and retrieve console.log/warn/error messages via chrome.debugger API
- browser_errors: Capture JavaScript errors and exceptions with stack traces

Implementation uses lazy debugger attachment with automatic cleanup on tab close.
Max 1000 log entries per tab to prevent memory issues.

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