初始化web服务功能

src/app/page.tsx

@@ -2,11 +2,43 @@
 
 import { useEffect } from "react"
 import { useRouter } from "next/navigation"
+import { isDesktop } from "@/lib/platform"
 
 export default function Page() {
   const router = useRouter()
   useEffect(() => {
-    router.replace("/welcome")
+    if (isDesktop()) {
+      router.replace("/welcome")
+      return
+    }
+    // Web mode: validate token before entering app
+    const token = localStorage.getItem("codeg_token")
+    if (!token) {
+      router.replace("/login")
+      return
+    }
+    // Verify token is still valid
+    fetch("/api/health", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        Authorization: `Bearer ${token}`,
+      },
+      body: "{}",
+    })
+      .then((res) => {
+        if (res.ok) {
+          router.replace("/welcome")
+        } else {
+          localStorage.removeItem("codeg_token")
+          router.replace("/login")
+        }
+      })
+      .catch(() => {
+        // Server unreachable
+        localStorage.removeItem("codeg_token")
+        router.replace("/login")
+      })
   }, [router])
   return null
 }