Fix error propagation in forms

docs/FORM_SUBMISSION_PATTERNS.md

@@ -122,6 +122,9 @@ export function EntityForm({ onSubmit, onCancel, initialData }: EntityFormProps)
           action: initialData?.id ? 'Update Entity' : 'Create Entity',
           metadata: { entityName: data.name }
         });
+        
+        // ⚠️ CRITICAL: Re-throw so parent can handle modal state
+        throw error;
       }
     })}>
       {/* Form fields */}
@@ -177,33 +180,64 @@ export function EntityListPage() {
 
 ## Error Handling
 
-### Form-Level Errors
-Forms use `handleError` utility for errors:
+### ⚠️ CRITICAL: Error Propagation Pattern
+
+Forms MUST re-throw errors after logging them so parent components can respond appropriately (keep modals open, show additional context, etc.).
+
+**Forms MUST re-throw errors:**
 ```typescript
-try {
-  await onSubmit(data);
 } catch (error: unknown) {
+  // Log error for debugging and show toast to user
   handleError(error, {
-    action: 'Create Park',
+    action: 'Submit Park',
     userId: user?.id,
     metadata: { parkName: data.name }
   });
+  
+  // ⚠️ CRITICAL: Re-throw so parent can handle modal state
+  throw error;
 }
 ```
 
-### Parent-Level Errors
-Parent pages can catch errors for additional handling:
+**Why Re-throw?**
+- Parent needs to know submission failed
+- Modal should stay open so user can retry
+- User can fix validation issues and resubmit
+- Prevents "success" behavior on failures
+- Maintains proper error flow through the app
+
+### Parent-Level Error Handling
+
 ```typescript
-try {
-  await submitEntityCreation(data, user.id);
-  toast({ title: "Success" });
-  setIsModalOpen(false);
-} catch (error) {
-  // Form already showed error toast
-  // Parent can log or handle specific cases
-  if (error.code === 'DUPLICATE_SLUG') {
-    // Handle specific error
+const handleParkSubmit = async (data: FormData) => {
+  try {
+    await submitParkCreation(data, user.id);
+    toast.success('Park submitted for review');
+    setIsModalOpen(false); // Only close on success
+  } catch (error) {
+    // Error already toasted by form via handleError()
+    // Modal stays open automatically because we don't close it
+    // User can fix issues and retry
+    console.error('Submission failed:', error);
   }
+};
+```
+
+**Expected Error Flow:**
+1. User submits form → `onSubmit()` called
+2. Submission fails → Form catches error
+3. Form shows error toast via `handleError()`
+4. Form re-throws error to parent
+5. Parent's catch block executes
+6. Modal stays open (no `setIsModalOpen(false)`)
+7. User fixes issue and tries again
+
+**Common Mistake:**
+```typescript
+// ❌ WRONG - Error not re-thrown, parent never knows
+} catch (error: unknown) {
+  handleError(error, { action: 'Submit' });
+  // Missing: throw error;
 }
 ```