feat(notifications): add notification system and wire order/dispute events

app/(account)/notifications/page.tsx

@@ -56,7 +56,7 @@ export default function NotificationsPage() {
   const systemNotifs = notifications.filter((notification) => notification.type === "system")
 
   return (
-    <div className="max-w-2xl space-y-6">
+    <div className="max-w-2xl mx-auto space-y-6">
       <div className="flex items-center justify-between">
         <div className="flex items-center gap-2">
           <h1 className="text-2xl font-bold">通知中心</h1>
@@ -76,13 +76,21 @@ export default function NotificationsPage() {
           <TabsTrigger value="system">系统</TabsTrigger>
         </TabsList>
 
-        <TabsContent value="all" className="space-y-2 mt-4">
-          {notifications.map((notification) => (
-            <NotificationItem key={notification.id} notification={notification} />
-          ))}
+        <TabsContent value="all" className="space-y-3 mt-4">
+          {notifications.length === 0 ? (
+            <Card>
+              <CardContent className="py-8 text-center text-sm text-muted-foreground">
+                暂无通知
+              </CardContent>
+            </Card>
+          ) : (
+            notifications.map((notification) => (
+              <NotificationItem key={notification.id} notification={notification} />
+            ))
+          )}
         </TabsContent>
 
-        <TabsContent value="order" className="space-y-2 mt-4">
+        <TabsContent value="order" className="space-y-3 mt-4">
           {orderNotifs.length === 0 ? (
             <Card>
               <CardContent className="py-8 text-center text-sm text-muted-foreground">
@@ -94,7 +102,7 @@ export default function NotificationsPage() {
           )}
         </TabsContent>
 
-        <TabsContent value="community" className="space-y-2 mt-4">
+        <TabsContent value="community" className="space-y-3 mt-4">
           {communityNotifs.length === 0 ? (
             <Card>
               <CardContent className="py-8 text-center text-sm text-muted-foreground">
@@ -106,7 +114,7 @@ export default function NotificationsPage() {
           )}
         </TabsContent>
 
-        <TabsContent value="system" className="space-y-2 mt-4">
+        <TabsContent value="system" className="space-y-3 mt-4">
           {systemNotifs.length === 0 ? (
             <Card>
               <CardContent className="py-8 text-center text-sm text-muted-foreground">