feat(dashboard): boarding-pass hero, atlas row, live widgets + modal portal fix

Reworked dashboard layout: boarding-pass hero with hover + days-left countdown, atlas stats row with real flags, searchable currency widget, editable timezone widget, new-trip FAB. Modals now portal to document.body to avoid inheriting dashboard-scoped button/font styles.

client/src/components/shared/Modal.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useCallback, useRef } from 'react'
+import ReactDOM from 'react-dom'
 import { X } from 'lucide-react'
 
 const sizeClasses: Record<string, string> = {
@@ -48,7 +49,7 @@ export default function Modal({
 
   if (!isOpen) return null
 
-  return (
+  return ReactDOM.createPortal(
     <div
       className="fixed inset-0 z-[200] flex items-start sm:items-center justify-center px-4 modal-backdrop trek-backdrop-enter"
       style={{ backgroundColor: 'rgba(15, 23, 42, 0.5)', paddingTop: 70, paddingBottom: 'calc(20px + var(--bottom-nav-h))', overflow: 'hidden' }}
@@ -94,6 +95,7 @@ export default function Modal({
         )}
       </div>
 
-    </div>
+    </div>,
+    document.body
   )
 }