fix(admin): login redirect — full location.href=/ instead of hash, session check on mount

- window.location.href='/' after login (was window.location.hash='/' which stayed on /login#/)
- checkSession on mount: already-authenticated users skip login form

admin-next/src/app/login/page.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState } from "react";
+import { useEffect, useState } from "react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -18,7 +18,16 @@ import { toast } from "sonner";
 export function LoginPage() {
   const [token, setToken] = useState("");
   const [loading, setLoading] = useState(false);
-  const { login } = useAuthStore();
+  const { login, checkSession } = useAuthStore();
+
+  // Если сессия уже активна — сразу в админку (не показывать форму)
+  useEffect(() => {
+    checkSession().then((ok) => {
+      if (ok) {
+        window.location.href = "/";
+      }
+    });
+  }, [checkSession]);
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
@@ -43,7 +52,8 @@ export function LoginPage() {
         const { role } = await sessionRes.json();
         login(role);
         toast.success("Logged in successfully");
-        window.location.hash = "/";
+        // Полный редирект в корень админки (AppPage сам решает, показывать ли Dashboard)
+        window.location.href = "/";
       } else {
         toast.error("Session verification failed. Please try again.");
       }