refactor: split frontend application features

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/components/actions/Account.tsx

@@ -0,0 +1,47 @@
+import { useEffect, useState } from 'react'
+import { useNavigate } from 'react-router-dom'
+import { authStorage, invalidateSession, SESSION_EXPIRED_EVENT } from '../../api/client'
+
+export function useAuthSession() {
+  const [authenticated, setAuthenticated] = useState(() => Boolean(authStorage.token()))
+  const [sessionExpired, setSessionExpired] = useState(false)
+  const navigate = useNavigate()
+
+  useEffect(() => {
+    function handleSessionExpired() {
+      setAuthenticated(false)
+      setSessionExpired(true)
+      navigate('/login', { replace: true })
+    }
+
+    window.addEventListener(SESSION_EXPIRED_EVENT, handleSessionExpired)
+    return () => window.removeEventListener(SESSION_EXPIRED_EVENT, handleSessionExpired)
+  }, [navigate])
+
+  useEffect(() => {
+    if (!authenticated) return
+    const expiresAt = authStorage.expiresAt()
+    if (expiresAt === null) return
+    const remaining = expiresAt - Date.now()
+    if (remaining <= 0) {
+      invalidateSession()
+      return
+    }
+    const timeout = window.setTimeout(invalidateSession, remaining)
+    return () => window.clearTimeout(timeout)
+  }, [authenticated])
+
+  function completeLogin() {
+    setAuthenticated(true)
+    setSessionExpired(false)
+    navigate('/jobs', { replace: true })
+  }
+
+  function logout() {
+    authStorage.clear()
+    setAuthenticated(false)
+    setSessionExpired(false)
+  }
+
+  return { authenticated, sessionExpired, completeLogin, logout }
+}