feat(frontend): add done-for-day summary card to CurrentAppointment, fix schedule z-index

Replace current/next card with done-for-day summary state when all appointments are finished. Shows daily stats (payments, tips, duration, customers) and week summary when tomorrow is closed. Fix schedule grid z-index to remove stacking context that caused overlay issues.

Ultraworked with Sisyphus

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/src/routes/admin/schedule/+page.svelte

@@ -487,7 +487,7 @@
 						<!-- 2. GRID CONTAINER (Day Columns) -->
 						<div class="relative flex flex-1 flex-col">
 							<!-- Grid Rows & Cells -->
-							<div class="relative z-0">
+							<div class="relative">
 								{#each timeRange.hours as h (h)}
 									<div class="flex border-b border-gray-100">
 										{#each getWeekDays(weekStart) as day (formatDate(day))}
@@ -594,7 +594,7 @@
 							</div>
 
 							<!-- 3. OVERLAY LAYER (Lines & Closed Stripes) -->
-							<!-- z-5 places it above grid backgrounds (z-0) but below bookings (z-10) -->
+							<!-- z-5: below bookings (z-10) since grid no longer creates a stacking context -->
 							<div class="pointer-events-none absolute inset-0 z-5">
 								{#each getWeekDays(weekStart) as day, dayIdx (formatDate(day))}
 									{@const dateStr = formatDate(day)}