fix: correctly validate number inputs against null/NaN bypass in admin modals

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

@@ -50,11 +50,31 @@ import { Button } from '$lib/components/ui/button';
 	}
 
 	function validateNoticeDurationField() {
-		formErrors.notice_duration = (formData.notice_duration_hours < 0 || isNaN(formData.notice_duration_hours)) ? 'Must be a positive number' : '';
+		const val = formData.notice_duration_hours;
+		if (val === null || val === undefined || val === '') {
+			formErrors.notice_duration = 'Must be a positive number';
+			return;
+		}
+		const num = Number(val);
+		if (isNaN(num) || num < 0 || !Number.isInteger(num)) {
+			formErrors.notice_duration = 'Must be a positive whole number';
+		} else {
+			formErrors.notice_duration = '';
+		}
 	}
 
 	function validateExpiryField() {
-		formErrors.expiry = (formData.expiry_months < 1 || isNaN(formData.expiry_months)) ? 'Must be at least 1 month' : '';
+		const val = formData.expiry_months;
+		if (val === null || val === undefined || val === '') {
+			formErrors.expiry = 'Must be at least 1 month';
+			return;
+		}
+		const num = Number(val);
+		if (isNaN(num) || num < 1 || !Number.isInteger(num)) {
+			formErrors.expiry = 'Must be a whole number of at least 1 month';
+		} else {
+			formErrors.expiry = '';
+		}
 	}
 
 	function validateAllFields() {
@@ -68,10 +88,14 @@ import { Button } from '$lib/components/ui/button';
 		!formErrors.name &&
 		!formErrors.notice_duration &&
 		!formErrors.expiry &&
-		formData.notice_duration_hours >= 0 &&
-		!isNaN(formData.notice_duration_hours) &&
-		formData.expiry_months >= 1 &&
-		!isNaN(formData.expiry_months)
+		formData.notice_duration_hours !== null &&
+		formData.notice_duration_hours !== undefined &&
+		formData.notice_duration_hours !== '' &&
+		Number(formData.notice_duration_hours) >= 0 &&
+		formData.expiry_months !== null &&
+		formData.expiry_months !== undefined &&
+		formData.expiry_months !== '' &&
+		Number(formData.expiry_months) >= 1
 	);
 
 	async function fetchData() {

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

@@ -40,6 +40,9 @@
 	let serviceErrors = $state<Record<string, string>>({});
 
 	function validatePrice(price: any): string {
+		if (price === null || price === undefined || price === '') {
+			return 'Price is required';
+		}
 		const numPrice = parseFloat(price);
 		if (isNaN(numPrice)) {
 			return 'Price must be a valid number';
@@ -57,20 +60,24 @@
 		return '';
 	}
 
-	function validateDuration(value: number, field: string): string {
-		if (isNaN(value)) {
+	function validateDuration(value: any, field: string): string {
+		if (value === null || value === undefined || value === '') {
+			return 'Field cannot be empty';
+		}
+		const num = Number(value);
+		if (isNaN(num)) {
 			return 'Must be a valid number';
 		}
 
-		if (!Number.isInteger(value)) {
+		if (!Number.isInteger(num)) {
 			return 'Must be a whole number';
 		}
 
-		if (field === 'duration_minutes' && value <= 0) {
+		if (field === 'duration_minutes' && num <= 0) {
 			return 'Duration must be greater than 0';
 		}
 
-		if (field === 'minimum_age_required' && (value < 0 || value > 100)) {
+		if (field === 'minimum_age_required' && (num < 0 || num > 100)) {
 			return 'Must be between 0 and 100';
 		}