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.

frontend/src/lib/components/booking/BookingActions.svelte

@@ -0,0 +1,31 @@
+<script lang="ts">
+	import { createEventDispatcher } from 'svelte';
+	import { Button } from '$lib/components/ui/button';
+
+	export let canBack = false;
+	export let canNext = false;
+	export let isSubmitting = false;
+	export let nextLabel = 'Next';
+	export let submitLabel = 'Submit';
+	export let showSubmit = false;
+
+	const dispatch = createEventDispatcher();
+</script>
+
+<div class="flex justify-between">
+	<Button variant="outline" disabled={!canBack} onclick={() => dispatch('back')}>Back</Button>
+
+	{#if showSubmit}
+		<Button
+			disabled={!canNext || isSubmitting}
+			onclick={() => dispatch('submit')}
+			class="bg-primary text-primary-foreground"
+		>
+			{isSubmitting ? 'Processing...' : submitLabel}
+		</Button>
+	{:else}
+		<Button disabled={!canNext} onclick={() => dispatch('next')}>
+			{nextLabel}
+		</Button>
+	{/if}
+</div>