Sync shared components — sidebar scrollbar, Layout, AuthGate updates

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/AuthGate.tsx

@@ -1,10 +1,12 @@
 import { useEffect, useRef, useState } from 'react'
 import type { User } from '../types'
 
-const SHARED_TIMEOUT_MS = 10 * 60 * 1000
-
-function isSharedDevice() {
-  return document.cookie.split(';').some(c => c.trim() === 'hnf_shared_device=1')
+function getInactivityMs(): number | undefined {
+  if (window.matchMedia('(display-mode: standalone)').matches) return undefined
+  const c = document.cookie.split(';').map(s => s.trim()).find(s => s.startsWith('hnf_inactivity_mins='))
+  if (!c) return undefined
+  const mins = parseInt(c.split('=')[1])
+  return isNaN(mins) || mins <= 0 ? undefined : mins * 60 * 1000
 }
 
 
@@ -42,7 +44,8 @@ export function AuthGate({ children }: Props) {
   }, [])
 
   useEffect(() => {
-    if (state !== 'authed' || !isSharedDevice()) return
+    const ms = getInactivityMs()
+    if (state !== 'authed' || !ms) return
 
     async function forceLogout() {
       await fetch('/api/auth/logout', { method: 'POST', credentials: 'include' }).catch(() => {})
@@ -52,7 +55,7 @@ export function AuthGate({ children }: Props) {
 
     function reset() {
       if (timerRef.current) clearTimeout(timerRef.current)
-      timerRef.current = setTimeout(forceLogout, SHARED_TIMEOUT_MS)
+      timerRef.current = setTimeout(forceLogout, ms)
     }
 
     const events = ['mousemove', 'keydown', 'click', 'touchstart'] as const