enhance(citation): render citations server-side (#39373)

Replace citation-js with a Go port of ruby-cff, which GitHub uses for
"Cite this repository", rendering APA and BibTeX server-side and
dropping about 770KB of JS. Output matches GitHub on 1568 of 1571
real-world files, the rest are improvements over GitHub.

- `CITATION.cff` wins over `CITATION.bib`, matched case-insensitively
and through symlinks
- `CITATION.bib` is offered as-is, without APA

Signed-off-by: silverwind <me@silverwind.io>

package.json

@@ -6,10 +6,6 @@
     "pnpm": ">= 11.0.0"
   },
   "dependencies": {
-    "@citation-js/core": "0.7.21",
-    "@citation-js/plugin-bibtex": "0.7.21",
-    "@citation-js/plugin-csl": "0.7.22",
-    "@citation-js/plugin-software-formats": "0.6.2",
     "@codemirror/autocomplete": "6.20.3",
     "@codemirror/commands": "6.11.1",
     "@codemirror/lang-json": "6.0.2",