feat(bookings): improve admin booking wizard and user dashboard

Backend:
- Enriched GetAllUserBookings response with calculated total_amount,
  amount_paid, and duration_minutes.
- Refactored GetBookingHandler to return a flat booking object matching
  frontend expectations.
- Added account_role to admin user list response and sorted users by
  booking activity.
- Corrected function name oo to AdminCreateBookingForUserHandler.

Frontend:
- Rebuilt BookingCreateModal into a 4-step wizard supporting guest
  bookings, service overrides, and real-time availability checks.
- Fixed account dashboard logic to correctly identify upcoming vs past
  bookings and sort unpaid items to the top.
- Extracted booking flow into a shared BookingFlow component.
- Redirected admin users from home page to /today.

backend/handlers/bookings/manage.go

@@ -173,10 +173,10 @@ type AdminCreateBookingForUserRequest struct {
 	StartTime        time.Time         `json:"start_time" validate:"required"`
 	ServiceIDs       []string          `json:"service_ids" validate:"required,min=1"`
 	ServiceOverrides []ServiceOverride `json:"service_overrides,omitempty"`
-	Notes            *string           `json:"notes,omitempty"` // staff notes
+	Notes            *string           `json:"notes,omitempty"` // appointment notes, visible to customers and staff
 }
 
-func oo(w http.ResponseWriter, r *http.Request) {
+func AdminCreateBookingForUserHandler(w http.ResponseWriter, r *http.Request) {
 	// Admin identity (creator)
 	adminID, ok := r.Context().Value(mw.UserIDKey).(string)
 	if !ok || adminID == "" {