Move the console onto ReUI PRO

Install ReUI (MCP, skill, @reui registry, Tailwind v4, shadcn base-nova) and move
the shared UI onto it: Button, Tag, Check, Input/Textarea, Segmented, Alert, Panel,
Dialog, Tooltip, Menu and Select (Popover), Toast (sonner), the Table frame
(DataGrid), the Dashboard KPI strip, the shnt Ops palette, Geist and the type scale.

Design only: behaviour, texts and roles are unchanged. Tests that asserted the old
DOM were updated; the tests now format numbers in English wherever they run.
docs/reui-migration-plan.md records the plan and its decisions.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/hooks/use-mobile.ts

@@ -0,0 +1,19 @@
+import * as React from "react"
+
+const MOBILE_BREAKPOINT = 768
+
+export function useIsMobile() {
+  const [isMobile, setIsMobile] = React.useState<boolean | undefined>(undefined)
+
+  React.useEffect(() => {
+    const mql = window.matchMedia(`(max-width: ${MOBILE_BREAKPOINT - 1}px)`)
+    const onChange = () => {
+      setIsMobile(window.innerWidth < MOBILE_BREAKPOINT)
+    }
+    mql.addEventListener("change", onChange)
+    setIsMobile(window.innerWidth < MOBILE_BREAKPOINT)
+    return () => mql.removeEventListener("change", onChange)
+  }, [])
+
+  return !!isMobile
+}