feat: restore auth state from backend session on app load

Call GET /api/v1/users/me on startup to rehydrate Zustand auth store
from the existing JToken cookie, so login survives page refresh.

app/providers.tsx

@@ -3,11 +3,34 @@
 import { GlobalLoginDialog } from "@/components/global-login-dialog"
 import { ThemeSyncEffect } from "@/components/theme-sync"
 import { TooltipProvider } from "@/components/ui/tooltip"
+import { getCurrentUserForLogin } from "@/lib/api"
+import { useAuthStore } from "@/store/auth"
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query"
 import { ThemeProvider } from "next-themes"
-import { useState } from "react"
+import { useEffect, useRef, useState } from "react"
 import { Toaster } from "sonner"
 
+function AuthBootstrap() {
+  const login = useAuthStore((s) => s.login)
+  const isAuthenticated = useAuthStore((s) => s.isAuthenticated)
+  const tried = useRef(false)
+
+  useEffect(() => {
+    if (tried.current || isAuthenticated) return
+    tried.current = true
+
+    getCurrentUserForLogin()
+      .then((user) => {
+        login(user, user.verifiedRoles ?? ["consumer"])
+      })
+      .catch(() => {
+        // no valid session — stay logged out
+      })
+  }, [login, isAuthenticated])
+
+  return null
+}
+
 export function Providers({ children }: { children: React.ReactNode }) {
   const [queryClient] = useState(
     () =>
@@ -26,6 +49,7 @@ export function Providers({ children }: { children: React.ReactNode }) {
       <ThemeProvider attribute="class" defaultTheme="system" enableSystem disableTransitionOnChange>
         <TooltipProvider>
           <ThemeSyncEffect />
+          <AuthBootstrap />
           {children}
           <Toaster richColors position="top-center" />
           <GlobalLoginDialog />