[codex] fix web highlight build config

[piti6]

Summary

• Add web-specific Re:VIEW config files that enable Rouge at the top level for web builds
• Keep EPUB configs without HTML highlighting
• Switch build-web.sh to use the web configs for Japanese and English output

Verification

• bundle exec ruby -rreview -rreview/configure -rreview/highlighter ... confirmed web configs return html="rouge" and EPUB configs return false
• Sample C# text produces Rouge markup for web config and stays plain for EPUB config
• git diff --check origin/main..HEAD