fix(i18n): replace hardcoded Chinese strings in Session Manager

- Add i18n keys for relative time (justNow, minutesAgo, hoursAgo, daysAgo)
- Add i18n keys for role labels (roleUser, roleSystem, roleTool)
- Add i18n keys for UI elements (tocTitle, searchSessions, clickToCopyPath)
- Update formatRelativeTime and getRoleLabel to accept t function
- Add useTranslation hook to SessionToc component

src/components/sessions/SessionItem.tsx

@@ -70,7 +70,7 @@ export function SessionItem({
       <div className="flex items-center gap-1 text-[11px] text-muted-foreground">
         <Clock className="size-3" />
         <span>
-          {lastActive ? formatRelativeTime(lastActive) : t("common.unknown")}
+          {lastActive ? formatRelativeTime(lastActive, t) : t("common.unknown")}
         </span>
       </div>
     </button>

src/components/sessions/SessionManagerPage.tsx

@@ -288,7 +288,7 @@ export function SessionManagerPage() {
                             <Search className="size-3.5" />
                           </Button>
                         </TooltipTrigger>
-                        <TooltipContent>搜索会话</TooltipContent>
+                        <TooltipContent>{t("sessionManager.searchSessions")}</TooltipContent>
                       </Tooltip>
 
                       <Select
@@ -482,7 +482,7 @@ export function SessionManagerPage() {
                                   {selectedSession.projectDir}
                                 </p>
                                 <p className="text-muted-foreground mt-1">
-                                  点击复制路径
+                                  {t("sessionManager.clickToCopyPath")}
                                 </p>
                               </TooltipContent>
                             </Tooltip>

src/components/sessions/SessionMessageItem.tsx

@@ -59,7 +59,7 @@ export function SessionMessageItem({
       </Tooltip>
       <div className="flex items-center justify-between text-xs mb-1.5 pr-6">
         <span className={cn("font-semibold", getRoleTone(message.role))}>
-          {getRoleLabel(message.role)}
+          {getRoleLabel(message.role, t)}
         </span>
         {message.ts && (
           <span className="text-muted-foreground">

src/components/sessions/SessionToc.tsx

@@ -1,4 +1,5 @@
 import { List, X } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { cn } from "@/lib/utils";
 import { Button } from "@/components/ui/button";
 import { ScrollArea } from "@/components/ui/scroll-area";
@@ -26,6 +27,7 @@ export function SessionTocSidebar({
   items,
   onItemClick,
 }: SessionTocSidebarProps) {
+  const { t } = useTranslation();
   if (items.length <= 2) return null;
 
   return (
@@ -33,7 +35,7 @@ export function SessionTocSidebar({
       <div className="p-3 border-b">
         <div className="flex items-center gap-1.5 text-xs font-medium text-muted-foreground">
           <List className="size-3.5" />
-          <span>对话目录</span>
+          <span>{t("sessionManager.tocTitle")}</span>
         </div>
       </div>
       <ScrollArea className="h-[calc(100%-40px)]">
@@ -74,6 +76,7 @@ export function SessionTocDialog({
   open,
   onOpenChange,
 }: SessionTocDialogProps) {
+  const { t } = useTranslation();
   if (items.length <= 2) return null;
 
   return (
@@ -95,11 +98,11 @@ export function SessionTocDialog({
         <DialogHeader className="px-4 py-3 relative border-b">
           <DialogTitle className="flex items-center gap-2 text-base font-semibold">
             <List className="size-4 text-primary" />
-            对话目录
+            {t("sessionManager.tocTitle")}
           </DialogTitle>
           <DialogClose
             className="absolute right-3 top-1/2 -translate-y-1/2 rounded-full p-1.5 hover:bg-muted transition-colors focus:outline-none focus:ring-2 focus:ring-primary focus:ring-offset-2"
-            aria-label="关闭"
+            aria-label={t("common.close")}
           >
             <X className="size-4 text-muted-foreground" />
           </DialogClose>

src/components/sessions/utils.ts

@@ -17,7 +17,10 @@ export const formatTimestamp = (value?: number) => {
   return new Date(value).toLocaleString();
 };
 
-export const formatRelativeTime = (value?: number) => {
+export const formatRelativeTime = (
+  value: number | undefined,
+  t: (key: string, options?: Record<string, unknown>) => string
+) => {
   if (!value) return "";
   const now = Date.now();
   const diff = now - value;
@@ -25,10 +28,10 @@ export const formatRelativeTime = (value?: number) => {
   const hours = Math.floor(diff / 3600000);
   const days = Math.floor(diff / 86400000);
 
-  if (minutes < 1) return "刚刚";
-  if (minutes < 60) return `${minutes} 分钟前`;
-  if (hours < 24) return `${hours} 小时前`;
-  if (days < 7) return `${days} 天前`;
+  if (minutes < 1) return t("sessionManager.justNow");
+  if (minutes < 60) return t("sessionManager.minutesAgo", { count: minutes });
+  if (hours < 24) return t("sessionManager.hoursAgo", { count: hours });
+  if (days < 7) return t("sessionManager.daysAgo", { count: days });
   return new Date(value).toLocaleDateString();
 };
 
@@ -57,12 +60,15 @@ export const getRoleTone = (role: string) => {
   return "text-muted-foreground";
 };
 
-export const getRoleLabel = (role: string) => {
+export const getRoleLabel = (
+  role: string,
+  t: (key: string) => string
+) => {
   const normalized = role.toLowerCase();
   if (normalized === "assistant") return "AI";
-  if (normalized === "user") return "用户";
-  if (normalized === "system") return "系统";
-  if (normalized === "tool") return "工具";
+  if (normalized === "user") return t("sessionManager.roleUser");
+  if (normalized === "system") return t("sessionManager.roleSystem");
+  if (normalized === "tool") return t("sessionManager.roleTool");
   return role;
 };