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"

src/ui/sidebar/CredentialEditorView.tsx

@@ -183,7 +183,7 @@ export function CredentialEditorView({
                 {t("hosts.friendlyNameLabel")}
               </label>
               <Input
-                placeholder="e.g. Production SSH Key"
+                placeholder={t("placeholders.credentialName")}
                 value={credForm.name}
                 onChange={(e) => setCredField("name", e.target.value)}
               />
@@ -203,7 +203,7 @@ export function CredentialEditorView({
                 {t("hosts.descriptionLabel")}
               </label>
               <Input
-                placeholder="Optional details..."
+                placeholder={t("placeholders.optionalDetails")}
                 value={credForm.description}
                 onChange={(e) => setCredField("description", e.target.value)}
               />
@@ -278,7 +278,7 @@ export function CredentialEditorView({
                 {t("hosts.username")}
               </label>
               <Input
-                placeholder="e.g. root or deploy"
+                placeholder={t("placeholders.sshUsername")}
                 value={credForm.username}
                 onChange={(e) => setCredField("username", e.target.value)}
               />

src/ui/sidebar/HostEditor.tsx

@@ -1444,7 +1444,7 @@ export function HostEditor({
                   {t("hosts.friendlyNameLabel")}
                 </label>
                 <Input
-                  placeholder="e.g. Production SSH Key"
+                  placeholder={t("placeholders.credentialName")}
                   value={quickCredentialName}
                   onChange={(e) => setQuickCredentialName(e.target.value)}
                 />

src/ui/sidebar/HostEditorGeneralTab.tsx

@@ -208,7 +208,7 @@ export function HostEditorGeneralTab({
                 {t("hosts.addressIp")}
               </label>
               <Input
-                placeholder="10.0.0.1 or example.com"
+                placeholder={t("placeholders.hostAddress")}
                 value={form.ip}
                 onChange={(e) => setField("ip", e.target.value)}
               />
@@ -220,7 +220,7 @@ export function HostEditorGeneralTab({
                   {t("hosts.friendlyName")}
                 </label>
                 <Input
-                  placeholder="e.g. Web Server Production"
+                  placeholder={t("placeholders.hostName")}
                   value={form.name}
                   onChange={(e) => setField("name", e.target.value)}
                 />