Add shared empty states, customer product filters, and SSO handoff across dashboards.

Standardize list empty UI, searchable country fields, customer-products filter row, password/login polish, and one-time business dashboard handoff from the customer app.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/business/src/lib/handoff.ts

@@ -0,0 +1,32 @@
+import { consumeHandoff } from '../services/authService'
+import type { LoginResponse } from '../types/auth'
+
+let inFlight: Promise<LoginResponse | null> | null = null
+
+function takeHandoffTicketFromUrl(): string | null {
+  const params = new URLSearchParams(window.location.search)
+  const ticket = params.get('handoff')?.trim()
+  if (!ticket) return null
+
+  params.delete('handoff')
+  const query = params.toString()
+  const next = `${window.location.pathname}${query ? `?${query}` : ''}${window.location.hash}`
+  window.history.replaceState({}, '', next)
+  return ticket
+}
+
+/** Consumes `?handoff=` at most once per page load (safe under React Strict Mode). */
+export function completeHandoffIfPresent(): Promise<LoginResponse | null> {
+  if (!inFlight) {
+    inFlight = (async () => {
+      const ticket = takeHandoffTicketFromUrl()
+      if (!ticket) return null
+      try {
+        return await consumeHandoff(ticket)
+      } catch {
+        return null
+      }
+    })()
+  }
+  return inFlight
+}