Global refresh rate in Settings drives every live view and each machine's sampler; per-page pickers removed

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

web/src/prefs.ts

@@ -0,0 +1,32 @@
+// Global refresh rate: one setting for every live view. Kept in localStorage for instant
+// use and mirrored to the hub's UI prefs so it follows the login.
+import { useEffect, useState } from 'react'
+
+export const REFRESH_OPTIONS = [250, 500, 1000, 2000, 5000] as const
+export const DEFAULT_REFRESH = 2000
+// Lists that shell out on the host (services, cron, updates, machines) never poll faster than this.
+export const LIST_FLOOR = 2000
+const KEY = 'hamlab.refresh'
+
+export function getRefreshMs(): number {
+  const v = Number(localStorage.getItem(KEY))
+  return v >= 100 && v <= 60000 ? v : DEFAULT_REFRESH
+}
+
+export function setRefreshMs(ms: number) {
+  localStorage.setItem(KEY, String(ms))
+  window.dispatchEvent(new CustomEvent('hamlab:refresh', { detail: ms }))
+}
+
+export function fmtMs(ms: number): string { return ms >= 1000 ? `${ms / 1000} s` : `${ms} ms` }
+
+// useRefreshMs re-renders the caller when the global rate changes.
+export function useRefreshMs(floor = 0): number {
+  const [ms, setMs] = useState(getRefreshMs())
+  useEffect(() => {
+    const h = (e: Event) => setMs((e as CustomEvent<number>).detail)
+    window.addEventListener('hamlab:refresh', h)
+    return () => window.removeEventListener('hamlab:refresh', h)
+  }, [])
+  return Math.max(ms, floor)
+}