style: fix prefer-const and prettier formatting issues

frontend/src/lib/components/admin/TimeBlockers.svelte

@@ -55,7 +55,7 @@
 		rescheduleVersion?: number;
 	}
 
-	let { openUserModal, openBookingModal, rescheduleVersion = 0 }: Props = $props();
+	const { openUserModal, openBookingModal, rescheduleVersion = 0 }: Props = $props();
 
 	const PAGE_SIZE = 5;
 
@@ -84,7 +84,7 @@
 
 	let overlappingBookings = $state<OverlappingBooking[]>([]);
 	let hasOverlap = $state(false);
-	let hasDayConflicts = $derived(overlappingBookings.length > 0);
+	const hasDayConflicts = $derived(overlappingBookings.length > 0);
 
 	let showDeleteAlert = $state(false);
 	let blockerToDelete = $state<TimeBlocker | null>(null);
@@ -128,9 +128,9 @@
 		return `${row.startTime}-${row.endTime}-${row.isOpen}`;
 	}
 
-	let selectedWorkingHours = $derived.by(() => getWorkingHoursForDate(newStartDate));
+	const selectedWorkingHours = $derived.by(() => getWorkingHoursForDate(newStartDate));
 
-	let availableStartOptions = $derived.by(() => {
+	const availableStartOptions = $derived.by(() => {
 		const wh = selectedWorkingHours;
 		if (!wh || !wh.isOpen) return [];
 		const startMin = timeToMinutes(wh.startTime);
@@ -154,7 +154,7 @@
 		return options;
 	});
 
-	let availableEndOptions = $derived.by(() => {
+	const availableEndOptions = $derived.by(() => {
 		const wh = selectedWorkingHours;
 		if (!wh || !wh.isOpen) return [];
 		const startMin = timeToMinutes(wh.startTime);
@@ -197,14 +197,14 @@
 		return `in ${Math.floor(hr / 24)}d`;
 	}
 
-	let sortedBlockers = $derived.by(() => {
+	const sortedBlockers = $derived.by(() => {
 		return [...blockers].sort(
 			(a, b) => new SvelteDate(a.start_time).getTime() - new SvelteDate(b.start_time).getTime()
 		);
 	});
 
-	let totalPages = $derived.by(() => Math.max(1, Math.ceil(sortedBlockers.length / PAGE_SIZE)));
-	let pagedBlockers = $derived.by(() => {
+	const totalPages = $derived.by(() => Math.max(1, Math.ceil(sortedBlockers.length / PAGE_SIZE)));
+	const pagedBlockers = $derived.by(() => {
 		const start = (currentPage - 1) * PAGE_SIZE;
 		return sortedBlockers.slice(start, start + PAGE_SIZE);
 	});
@@ -275,13 +275,13 @@
 		return formatLocalDateTime(dt);
 	}
 
-	let formComplete = $derived.by(() => {
+	const formComplete = $derived.by(() => {
 		return (
 			newDescription.trim() !== '' && newStartDate !== '' && startHour !== '' && endHour !== ''
 		);
 	});
 
-	let canCreate = $derived.by(() => {
+	const canCreate = $derived.by(() => {
 		return formComplete && !hasOverlap && !hasDayConflicts && !checkingOverlap;
 	});