fix(teacher): 统一详情页返回路径与中英文文案 (P1-3+P2-1)

P1-3: empty-state 默认按钮 variant 改为 outline 并新增 variant prop；button.tsx 导出 ButtonProps；统一 5 个详情页返回路径为 ghost+ArrowLeft+文字标签；course-plan-detail raw a 改为 Link。P2-1: formatLongDate 默认 locale 改为 zh-CN，weekday 改为 short；返回按钮文案中文化；course-plan-detail 全量中文化；grades/analytics 标题中文化。验证：tsc 0 错误，lint 0 错误，架构图 004/005 已同步。

src/app/(dashboard)/teacher/grades/analytics/page.tsx

@@ -46,14 +46,14 @@ export default async function GradeAnalyticsPage({
     return (
       <div className="h-full flex-1 flex-col space-y-8 p-8 md:flex">
         <div>
-          <h1 className="text-2xl font-bold tracking-tight">Grade Analytics</h1>
+          <h1 className="text-2xl font-bold tracking-tight">成绩分析</h1>
           <p className="text-muted-foreground">
-            Trend analysis, class comparisons, and score distributions.
+            趋势分析、班级对比与分数分布。
           </p>
         </div>
         <EmptyState
-          title="No classes"
-          description="You don't have any classes yet."
+          title="暂无班级"
+          description="您还没有任何班级。"
           icon={BarChart3}
           className="border-none shadow-none"
         />
@@ -98,15 +98,15 @@ export default async function GradeAnalyticsPage({
     <div className="h-full flex-1 flex-col space-y-6 p-8 md:flex">
       <div className="flex flex-col justify-between gap-4 md:flex-row md:items-center">
         <div>
-          <h1 className="text-2xl font-bold tracking-tight">Grade Analytics</h1>
+          <h1 className="text-2xl font-bold tracking-tight">成绩分析</h1>
           <p className="text-muted-foreground">
-            Trend analysis, class comparisons, and score distributions.
+            趋势分析、班级对比与分数分布。
           </p>
         </div>
-        <Button asChild variant="outline">
+        <Button asChild variant="ghost" size="sm">
           <Link href="/teacher/grades">
             <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
-            Back to Grades
+            返回成绩列表
           </Link>
         </Button>
       </div>

src/app/(dashboard)/teacher/homework/assignments/[id]/page.tsx

@@ -7,7 +7,7 @@ import { HomeworkAssignmentQuestionErrorOverviewCard } from "@/modules/homework/
 import { Badge } from "@/shared/components/ui/badge"
 import { Button } from "@/shared/components/ui/button"
 import { formatDate } from "@/shared/lib/utils"
-import { ChevronLeft, Users, Calendar, BarChart3, CheckCircle2 } from "lucide-react"
+import { ArrowLeft, Users, Calendar, BarChart3, CheckCircle2 } from "lucide-react"
 
 export const dynamic = "force-dynamic"
 
@@ -25,14 +25,12 @@ export default async function HomeworkAssignmentDetailPage({ params }: { params:
       <div className="border-b bg-background px-8 py-5">
         <div className="flex flex-col gap-4 md:flex-row md:items-start md:justify-between">
           <div className="min-w-0 flex flex-col gap-2">
-            <div className="flex items-center gap-2 text-sm text-muted-foreground mb-1">
-              <Link href="/teacher/homework/assignments" className="flex items-center hover:text-foreground transition-colors">
-                <ChevronLeft className="h-4 w-4 mr-1" aria-hidden="true" />
-                Assignments
+            <Button asChild variant="ghost" size="sm" className="w-fit">
+              <Link href="/teacher/homework/assignments">
+                <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
+                返回作业列表
               </Link>
-              <span aria-hidden="true">/</span>
-              <span>Details</span>
-            </div>
+            </Button>
             <div className="flex items-center gap-3">
               <h1 className="text-2xl font-bold tracking-tight text-foreground line-clamp-2">{assignment.title}</h1>
               <Badge variant={assignment.status === "published" ? "default" : "secondary"} className="capitalize">

src/app/(dashboard)/teacher/lesson-plans/new/page.tsx

@@ -10,12 +10,13 @@ export default function NewLessonPlanPage(): JSX.Element {
   return (
     <div className="p-6">
       <div className="mb-6 flex items-center gap-4">
-        <Button asChild variant="ghost" size="icon">
-          <Link href="/teacher/lesson-plans" aria-label="Back to lesson plans">
-            <ArrowLeft className="h-4 w-4" aria-hidden="true" />
+        <Button asChild variant="ghost" size="sm">
+          <Link href="/teacher/lesson-plans">
+            <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
+            返回备课列表
           </Link>
         </Button>
-        <h1 className="text-2xl font-bold tracking-tight">New Lesson Plan</h1>
+        <h1 className="text-2xl font-bold tracking-tight">新建课案</h1>
       </div>
       <TemplatePicker />
     </div>

src/app/(dashboard)/teacher/textbooks/[id]/page.tsx

@@ -31,9 +31,10 @@ export default async function TextbookDetailPage({
     <div className="flex flex-col h-[calc(100vh-4rem)] overflow-hidden">
       {/* Header / Nav (Fixed height) */}
       <div className="flex items-center gap-4 py-4 border-b shrink-0 bg-background z-10">
-        <Button variant="ghost" size="icon" asChild>
-          <Link href="/teacher/textbooks" aria-label="Back to textbooks">
-            <ArrowLeft className="h-4 w-4" aria-hidden="true" />
+        <Button asChild variant="ghost" size="sm">
+          <Link href="/teacher/textbooks">
+            <ArrowLeft className="mr-2 h-4 w-4" aria-hidden="true" />
+            返回教材列表
           </Link>
         </Button>
         <div className="flex-1 min-w-0">