Fix critical error handling gaps in submission pipeline

Addressed real error handling issues identified during comprehensive
pipeline review:

1. **process-selective-approval edge function**
   - Added try-catch blocks around idempotency key updates (lines 216-262)
   - Prevents silent failures when updating submission status tracking
   - Updates are now non-blocking to ensure proper response delivery

2. **submissionItemsService.ts**
   - Added error logging before throwing in fetchSubmissionItems (line 75-81)
   - Added error handling for park location fetch failures (lines 99-107)
   - Location fetch errors are now logged as non-critical and don't block
     submission item retrieval

3. **notify-moderators-submission edge function**
   - Added error handling for notification log insert (lines 216-236)
   - Log failures are now non-blocking and properly logged
   - Ensures notification delivery isn't blocked by logging issues

4. **upload-image edge function**
   - Fixed CORS headers scope issue (line 127)
   - Moved corsHeaders definition outside try block
   - Prevents undefined reference in catch block error responses

All changes maintain backward compatibility and improve pipeline
resilience without altering functionality. Error handling is now
consistent with non-blocking patterns for auxiliary operations.

supabase/functions/notify-moderators-submission/index.ts

@@ -213,7 +213,7 @@ serve(async (req) => {
     );
 
     // Log notification in notification_logs with idempotency key
-    await supabase.from('notification_logs').insert({
+    const { error: logError } = await supabase.from('notification_logs').insert({
       user_id: '00000000-0000-0000-0000-000000000000', // Topic-based
       notification_type: 'moderation_submission',
       idempotency_key: idempotencyKey,
@@ -225,13 +225,23 @@ serve(async (req) => {
       }
     });
 
+    if (logError) {
+      // Non-blocking - notification was sent successfully, log failure shouldn't fail the request
+      edgeLogger.warn('Failed to log notification in notification_logs', {
+        action: 'notify_moderators',
+        requestId: tracking.requestId,
+        error: logError.message,
+        submissionId: submission_id
+      });
+    }
+
     const duration = endRequest(tracking);
-    edgeLogger.info('Successfully notified all moderators via topic', { 
+    edgeLogger.info('Successfully notified all moderators via topic', {
       action: 'notify_moderators',
       requestId: tracking.requestId,
       traceId: tracking.traceId,
       duration,
-      transactionId: data?.transactionId 
+      transactionId: data?.transactionId
     });
 
     return new Response(