Fix Docker build by using path alias for queryClient import

Changed import from "./lib/queryClient" to "@/lib/queryClient"
to use the configured path alias which resolves correctly
in the Docker build environment.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

client/src/App.tsx

@@ -1,5 +1,5 @@
 import { Switch, Route } from "wouter";
-import { queryClient } from "./lib/queryClient";
+import { queryClient } from "@/lib/queryClient";
 import { QueryClientProvider } from "@tanstack/react-query";
 import { Toaster } from "@/components/ui/toaster";
 import { TooltipProvider } from "@/components/ui/tooltip";