fix 224 duplicate id errors for XHTML validation
remove source and phpinfo entry links
feat: show TOC sidebar and back-to-top only when content exceeds 80 lines (2 screens)
fix: use correct SourceForge thumbnail URL (750x400)
chore: use thumbnail instead of full screenshot in README
docs: translate README.md Chinese section to English
chore: update screenshot link, compress phpMan.php, prepare release
docs: add man/info/perldoc mode comparison section to README