feat(roles): add delete user functionality to role management

Add ability for Emperor to delete users from the role management panel:
- New POST /api/roles/delete endpoint with PROMOTE_USER permission guard,
  blocks deleting self or other emperors, cascades user data cleanup
- Trash button on each non-emperor row with confirmation dialog
- Auto-navigate to previous page when deleting the last user on a page
- i18n strings added for all 5 locales

app/api/roles/delete/route.ts

@@ -0,0 +1,49 @@
+import { createDb } from "@/lib/db";
+import { users, userRoles, apiKeys } from "@/lib/schema";
+import { eq } from "drizzle-orm";
+import { ROLES, PERMISSIONS } from "@/lib/permissions";
+import { checkPermission } from "@/lib/auth";
+import { getUserId } from "@/lib/apiKey";
+
+export const runtime = "edge";
+
+export async function POST(request: Request) {
+  const canManage = await checkPermission(PERMISSIONS.PROMOTE_USER);
+  if (!canManage) {
+    return Response.json({ error: "权限不足" }, { status: 403 });
+  }
+
+  try {
+    const { userId } = await request.json() as { userId: string };
+    if (!userId) {
+      return Response.json({ error: "缺少必要参数" }, { status: 400 });
+    }
+
+    const currentUserId = await getUserId();
+    if (userId === currentUserId) {
+      return Response.json({ error: "不能删除自己" }, { status: 400 });
+    }
+
+    const db = createDb();
+
+    const currentUserRole = await db.query.userRoles.findFirst({
+      where: eq(userRoles.userId, userId),
+      with: {
+        role: true,
+      },
+    });
+
+    if (currentUserRole?.role.name === ROLES.EMPEROR) {
+      return Response.json({ error: "不能删除皇帝" }, { status: 400 });
+    }
+
+    // apiKeys 未配置级联删除，需先手动删除；其余（accounts / emails→messages / webhooks / userRoles）由外键级联处理
+    await db.delete(apiKeys).where(eq(apiKeys.userId, userId));
+    await db.delete(users).where(eq(users.id, userId));
+
+    return Response.json({ success: true });
+  } catch (error) {
+    console.error("Failed to delete user:", error);
+    return Response.json({ error: "操作失败" }, { status: 500 });
+  }
+}