fix(i18n): complete Simplified Chinese core and plugin translations (#1542)

* fix(i18n): complete Chinese onboarding and navigation labels

* fix(i18n): translate remaining Chinese core and plugin interfaces

* fix(i18n): translate host editor tab overflow controls

* fix(i18n): use consistent Chinese fleet terminology

* fix(i18n): localize hardcoded controls and plugin views

* fix(i18n): translate built-in homepage widget catalog

* test(homepage): follow translated timezone placeholder

* fix(i18n): translate plugin-provided homepage widgets

* fix(i18n): localize feature settings section titles

src/ui/sidebar/AdminApiKeysSection.tsx

@@ -150,7 +150,7 @@ export function AdminApiKeysSection({
                     <span className="text-accent-brand">*</span>
                   </label>
                   <Input
-                    placeholder="e.g., CI Pipeline"
+                    placeholder={t("placeholders.apiKeyName")}
                     value={newKeyName}
                     onChange={(e) => setNewKeyName(e.target.value)}
                     className="text-xs"