Update Docusaurus and the documentation dependencies

[beetlebugorg]

What changes

Every open npm alert sits in docs/package-lock.json. None reaches the service. They are the Docusaurus build for the documentation site.

• Move @docusaurus/* from 3.7.0 to 3.10.2.
• Raise node-version to 22 in docs-pr.yml and docs-deploy.yml, and engines.node to >=20.0. Docusaurus 3.10 declares node >=20, and both workflows pinned 18.
• Move onBrokenMarkdownLinks under markdown.hooks. The old position is deprecated and is removed in Docusaurus 4.
• Override serialize-javascript and uuid. Docusaurus 3.10.2 still resolves 6.0.2 and 8.3.2 through its webpack tooling, and neither closes on the version bump alone.

npm audit goes from 31 findings, 1 low and 15 moderate and 15 high, to 17, all high and all one root cause.

What this closes

package	needed	before	after
@babel/core	7.29.6	7.27.1	7.29.7	closed
http-proxy-middleware	2.0.10	2.0.9	2.0.10	closed
joi	17.13.4	17.13.3	17.13.6	closed
minimatch	3.1.4	3.1.2	3.1.5	closed
path-to-regexp	0.1.13	0.1.12	0.1.13	closed
picomatch	2.3.2	2.3.1	2.3.2	closed
webpack-dev-server	5.2.6	4.15.2	5.2.6	closed
serialize-javascript	7.0.5	6.0.2	7.1.0	closed by override
uuid	11.1.1	8.3.2	11.1.1	closed by override
image-size		1.2.1	2.0.2	stays open

image-size stays open because no patched release exists. Its advisory names <= 2.0.2 with no fixed version, and 2.0.2 is the newest release. Docusaurus calls it at build time to size local images, so the input is the repository's own files.

Verify

npm ci and npm run build both succeed on Node 22, which is what the workflows now use. The deprecation warning is gone after the config move.

The rendered site is compared against a Docusaurus 3.7.0 build from main on Node 18. Both produce the same 30 pages. The visible text is identical on 29 of them. The one difference is the home page title, which 3.10 no longer doubles:

- go-dims | go-dims
+ go-dims

The two overrides were checked separately for behavior change. Building with and without them gives a byte-identical file set and 30 byte-identical HTML pages.