chore: update eslint and stylelint configs and re-sync modern-normalize (#38982)

- update the vendored `modern-normalize` to v3.0.1
- require descriptions for lint disables in TS and CSS, same as we
already have in Go.
- disable core rules covered by `regexp/*` and `unicorn/*`, and ones
that cannot fire
- stop applying vitest rules to the playwright files in `tests/e2e`
- enable 7 stylelint rules, mostly `no-unknown` and `no-invalid` checks
- drop 2 unnecessary vendor prefixes (safari v17+, chrome v120+)
- look up ids via `querySelector` with `CSS.escape` instead of
`getElementById`
- remove stale doc about `@ts-expect-error`, it's forbidden
- misc dev doc fixes

Every declaration that `modern-normalize` v3 removes was checked against
chromium, webkit and firefox defaults first. The `hr` color and the
`:-moz-focusring` outline are kept as documented deviations, dropping
those does change rendering.

---------

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/modules/user-settings.ts

@@ -1,4 +1,4 @@
-/* eslint-disable no-restricted-globals */
+/* eslint-disable no-restricted-globals -- this is the wrapper the rule points to */
 // Some people deploy Gitea under a subpath, so it needs prefix to avoid local storage key conflicts.
 // And these keys are for user settings only, it also needs a specific prefix,
 // in case in the future there are other uses of local storage, and/or we need to clear some keys when the quota is exceeded.