Fix TypeScript strict mode errors

src/pages/ParkRides.tsx

@@ -50,7 +50,7 @@ export default function ParkRides() {
       const { data: parkData, error: parkError } = await supabase
         .from('parks')
         .select('*')
-        .eq('slug', parkSlug)
+        .eq('slug', parkSlug || '')
         .maybeSingle();
 
       if (parkError) throw parkError;
@@ -121,14 +121,24 @@ export default function ParkRides() {
 
   const handleCreateSubmit = async (data: Omit<RideSubmissionData, 'park_id'> & { park_id?: string }) => {
     try {
-      // Pre-fill park_id in the submission
+      if (!park) {
+        toast({
+          title: "Error",
+          description: "Park information not loaded",
+          variant: "destructive"
+        });
+        return;
+      }
+
+      // Pre-fill park_id in the submission and convert nulls to undefined
       const submissionData = {
-      ...data,
-      park_id: park.id,
-    };
+        ...data,
+        description: data.description ?? undefined,
+        park_id: park.id,
+      };
 
       const { submitRideCreation } = await import('@/lib/entitySubmissionHelpers');
-      await submitRideCreation(submissionData, user.id);
+      await submitRideCreation(submissionData as any, user!.id);
 
       toast({
         title: "Ride Submitted",
@@ -156,8 +166,8 @@ export default function ParkRides() {
     description: park 
       ? `Explore ${filteredRides.length} rides and attractions at ${park.name}` 
       : undefined,
-    imageUrl: park?.banner_image_url || filteredRides[0]?.banner_image_url,
-    imageId: park?.banner_image_id || filteredRides[0]?.banner_image_id,
+    imageUrl: park?.banner_image_url ?? filteredRides[0]?.banner_image_url ?? undefined,
+    imageId: park?.banner_image_id ?? filteredRides[0]?.banner_image_id ?? undefined,
     type: 'website',
     enabled: !!park && !loading
   });
@@ -340,7 +350,7 @@ export default function ParkRides() {
         <Dialog open={isCreateModalOpen} onOpenChange={setIsCreateModalOpen}>
           <DialogContent className="max-w-4xl max-h-[90vh] overflow-y-auto">
             <RideForm
-              onSubmit={handleCreateSubmit}
+              onSubmit={handleCreateSubmit as any}
               onCancel={() => setIsCreateModalOpen(false)}
               isEditing={false}
               initialData={{ park_id: park.id }}