Supersedes #12345, which only moves the version and so is red on `build`,
`lint`, `test` and `config-examples`. v5 is a breaking release and the two
call sites have to move with it.

`scripts/validate-config-examples.mjs` now imports js-yaml as a namespace.
v5 dropped the CommonJS default export, so `import yaml from 'js-yaml'` failed
to load at all. That was also behind the three test failures: `yaml` was
`undefined`, `yaml.load` threw a `TypeError`, the script caught it and reported
"invalid YAML", so an example that should have failed AJV schema validation
failed at the parse step instead. All three pass on the import fix alone — no
v5 parsing behaviour change is involved.

`OptionsTable.tsx` drops `noCompatMode: true`, which v5 removed. It suppressed
YAML-1.1-compat quoting of `yes`/`no`/`on`/`off` and base-60 values. None of
the 136 defaults in the schema are one of those, so this is a no-op today; v5
quotes them by default and offers no way to opt out, so a future default of
`no` would start rendering as `"no"`.

`OptionsTable.tsx` also renames `quotingType: '"'` to `quoteStyle: 'double'`,
and this is the reason the bump is not mechanical. v5 renamed that option *and*
flipped its default to `'single'`, so just deleting the two options `tsc`
rejects silently reflows four published defaults. The worst is
`post_check.title`, whose value contains single quotes:

    before  "'{{ check_rule_name }}'{% if check_status == 'success' %} …"
    after   '''{{ check_rule_name }}''{% if check_status == ''success'' %} …'

Equivalent YAML, unreadable in a table people copy-paste from.

`@types/js-yaml` is dropped rather than bumped: v5 ships its own types, so the
stub is now a mismatched duplicate.

This goes to 5.3.0 rather than the 5.2.3 in #12345 because `^5.2.3` resolves to
5.3.0 anyway, and 5.3.0 only adds a custom-tag API this repo does not touch —
`dump` output is byte-identical between the two.

Verification: built the site on `main` and on this branch and diffed the
output — all 385 pages are byte-identical, so nothing readers see moves. Every
schema default also renders identically through `dumpDefault`. `pnpm check`,
`pnpm test` (172), `pnpm check:config-examples` (122 examples) and
`pnpm check:internal-leaks` are green, and a full build with OG generation on
produces 137 cards, same as `main`.