[chongfenglaosiji]

i18n(zh-CN): Settings navigation, Expectations and Themes

What & why

Next batch of the zh-CN catalog: Settings navigation, Expectations and Themes, as a data-only change.

Data-only: web/i18n/zh-CN.json is the only file touched. No Go, template or
JavaScript edits.

Scope

36 new keys:

Prefix	Keys	Covers
settings.section.*	16	The Settings navigation itself — every section name and description
settings.expectations.*	6	Post-apply checks: heading, rollback toggle and its help text
settings.theme.*	5	The colour-theme option names
settings.* (shared)	9	Settings heading, Save … settings button, saved/applied messages, nav aria label

Catalog goes from 63 shipped keys to 99 keys (32% of English). The
rest stays English by design, so nothing breaks.

Merge order (please read)

This diff is a snapshot of the whole file, so besides its own 36 keys it
contains the settings.default_language.auto wording fix that #131 also carries
(否则用英文 → 否则显示英文). Every batch PR sets that line to the same value, so they
merge cleanly in any order and none of them can silently revert it.

Checklist

• go build ./... compiles
• go test ./internal/i18n/ ./internal/server/ -run 'Translation|Catalog|Language|Locale' passes
• Commits are clean and the PR is focused on one concern
• Data-only, matching docs/TRANSLATING.md
• CHANGELOG.md / version bump — left to you, as before
• Licensed under Apache 2.0

Notes for reviewers

• settings.save_section is 保存{section}设置: the placeholder takes the already-translated section label, so no space is inserted around it in Chinese.
• settings.expectations.help + _after are split around the <em> holding settings.expectations.section_name; assembled it reads 在代理主机上定义的期望项（也就是它的期望项部分）会在每次配置同步后立即运行。
• The section labels here must match what the Go-side navigation resolves, which TestSettingsNavigationMatchesTheEnglishCatalog pins on the English side.

Verification — run against this exact file, in a Linux container (WSL):

go test ./internal/i18n/ ./internal/server/ -run 'Translation|Catalog|Language|Locale' -count=1
go build ./...

exit=0 — including TestEveryCatalogMatchesEnglishKeysAndPlaceholders and
TestEveryTranslationKeyUsedExistsInEnglish. Same as #131.

One note if you ever test on Windows: a plain checkout there fails
internal/caddy's TestBuildProxyRouteGolden, because that test compares bytes and
core.autocrlf makes the testdata/*.json golden files CRLF on disk while the
generated JSON is LF. It reproduces on an untouched main, so it is unrelated to this
PR — it is just why the run above is documented as Linux.

The pr2 log of that run is kept locally if you want it pasted here.

Catalog facts

• 99/99 keys valid; no key English does not have; no duplicate keys
• Placeholders identical to English on every key
• No empty values; UTF-8 without BOM; LF; no HTML in any value