Fill in the arXiv citation (2609.07398)

[knightnemo]

The preprint is up at https://arxiv.org/abs/2609.07398, so:

• README badge points at the abstract page instead of the XXXX.XXXXXX placeholder — and is now wrapped in a link (it was a bare <img>, unclickable)
• the Citation section carries the real BibTeX in place of TODO
• CITATION.cff gives GitHub's "Cite this repository" button the same entry

The BibTeX here is byte-identical with the project page's citation block and the personal-site bib file.

🤖 Generated with Claude Code

[wayrise]

Checked the things worth checking on a citation change:

• arXiv 2609.07398 is this paper — abstract page title matches the BibTeX exactly, submitted 7 Sep 2026.
• Author list is right and consistent in all three places — 24 authors, and the order in the BibTeX, the CITATION.cff top-level block and its preferred-citation block are identical to each other and to the arXiv listing, Yuran Wang through Hang Zhao.
• CITATION.cff parses as YAML, cff-version: 1.2.0, required keys present, preferred-citation well formed (type: article, year, url).
• lint and tests green.

Good catch on the badge, too — it had been a bare <img>, so the one badge people are most likely to click was the only unclickable one.

LGTM.