Fix: Add client-side validation

src/lib/entityValidationSchemas.ts

@@ -94,6 +94,12 @@ export const parkValidationSchema = z.object({
 }, {
   message: 'Closing date must be after opening date',
   path: ['closing_date'],
+}).refine((data) => {
+  // Either location object OR location_id must be provided
+  return !!(data.location || data.location_id);
+}, {
+  message: 'Location is required. Please search and select a location for the park.',
+  path: ['location']
 });
 
 // ============================================
@@ -280,6 +286,12 @@ export const rideValidationSchema = z.object({
     .max(1000, 'Submission notes must be less than 1000 characters')
     .nullish()
     .transform(val => val ?? undefined),
+}).refine((data) => {
+  // park_id is required (either real UUID or temp- reference)
+  return !!(data.park_id && data.park_id.trim().length > 0);
+}, {
+  message: 'Park is required. Please select or create a park for this ride.',
+  path: ['park_id']
 });
 
 // ============================================
@@ -774,3 +786,31 @@ export async function validateMultipleItems(
 
   return results;
 }
+
+/**
+ * Validate required fields before submission
+ * Returns user-friendly error messages
+ */
+export function validateRequiredFields(
+  entityType: keyof typeof entitySchemas,
+  data: any
+): { valid: boolean; errors: string[] } {
+  const errors: string[] = [];
+  
+  if (entityType === 'park') {
+    if (!data.location && !data.location_id) {
+      errors.push('Location is required. Please search and select a location for the park.');
+    }
+  }
+  
+  if (entityType === 'ride') {
+    if (!data.park_id || data.park_id.trim().length === 0) {
+      errors.push('Park is required. Please select or create a park for this ride.');
+    }
+  }
+  
+  return {
+    valid: errors.length === 0,
+    errors
+  };
+}