[zhangzhenghao]

Summary

• Locate the repository sidebar through PageLayout pane attributes and its About heading instead of generated CSS-module prefixes.
• Read the description from the About section and place related repositories after the Languages section without generated class selectors.
• Bump both Chrome and Firefox extension versions from 0.12 to 0.13.

Verification

• Reproduced missing neighbor requests against freshly fetched GitHub HTML before the fix.
• Passed scratch jsdom smoke checks using the actual content script and bundled jQuery: current GitRec HTML, class-free markup, empty descriptions, no Languages section, and Turbo-event idempotence.
• Passed node --check for all extension JavaScript files and git diff --check.
• Built and inspected Chrome/Firefox ZIPs, including manifest versions and referenced script entries.
• Independent review found no security or logic errors.

No unit-test files or temporary verification dependencies are added to the repository.