i18n(zh-CN): Dashboard

[chongfenglaosiji]

i18n(zh-CN): Dashboard

What & why

Next batch of the zh-CN catalog: Dashboard, as a data-only change.

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

Scope

107 new keys:

Prefix	Keys	Covers
dashboard.*	107	The whole Dashboard page

Catalog goes from 63 shipped keys to 170 keys (54% 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 107 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

• Placeholders kept as English has them: {count}, {server}, {domain}, {healthy}, {total}, {done}, {latest}, {current}. Example: 环境就绪情况 · 已完成 {done}/4 项必需项.
• dashboard.maintenance.global_active / global_detail / turn_off / restore are four fragments of one banner sentence; assembled it reads 全局维护模式已开启。 所有代理主机都在返回 503 页面。在设置中关闭 并同步 Caddy 以恢复服务。
• dashboard.traffic.description and dashboard.system.description take {server}, which is either the server name or the label from dashboard.traffic.active_node / dashboard.system.selected_node — both were translated so the sentence reads naturally either way.
• dashboard.activity.verb.* are deliberately neutral verbs (新建 / 删除 / 停用 / 启用 / 导入 / 重新分类 / 吊销), because the template combines them with different nouns.
• dashboard.fleet.last_seen is 最后活动 rather than a literal last-seen, matching the surrounding fleet wording.

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 pr3 log of that run is kept locally if you want it pasted here.

Catalog facts

• 170/170 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