docs: update citations and add Star History

[zhanghanduo]

Summary

• update the Apodex-1.1 citation with arXiv metadata
• add the FrontierChallenge citation
• replace the restricted hosted Star History API with self-hosted light and dark SVG charts
• refresh charts every two hours and publish them to an isolated star-history branch

Security and maintenance

• read stargazer history with the approved, repository-scoped STAR_HISTORY_TOKEN Actions secret
• pin all top-level Actions to commit SHAs
• keep chart publication isolated from main and validate SVG output before publishing
• reserve the workflow's contents: write permission for the native Git publishing job

Validation

• successful end-to-end Actions preview: token preflight, chart rendering, artifact transfer, SVG validation, and isolated branch publication
• public light and dark SVG URLs return HTTP 200
• YAML parse check
• git diff --check

The star-history branch has been seeded by the preview run. After merge, the two-hour schedule will keep the chart current.

[Copilot]

Pull request overview

Updates project documentation to keep citation metadata current and adds a theme-aware Star History embed to the README for better repository visibility.

Changes:

• Updated the Apodex-1.1 citation to include arXiv metadata (eprint, archivePrefix, primaryClass, URL).
• Added a new BibTeX citation entry for the FrontierChallenge work.
• Added a theme-aware Star History chart embed to the README using a <picture> element.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.