Firebase Authentication/Firestore Sync Issue - Fix Needed

## Project Overview

We need an urgent fix for a critical issue in our Next.js + Firebase application where user registration succeeds only approximately 50% of the time. This creates a frustrating user experience and administrative burden.

## Problem Details

Our othrwise simple application has an intermittent synchronization problem between Firebase Authentication and Firestore:

1. A user completes the registration form
2. The Firebase Authentication account is successfully created (~100% success rate)
3. The Firestore document creation attempt fails approximately 50% of the time
4. These "orphaned users" then cannot log in, receiving the error "Your account has not been approved yet"

This issue is especially problematic because:
- It occurs randomly with no clear pattern
- Some users report it works fine while others consistently encounter the problem
- Our admin panel doesn't display users who exist in Authentication but not in Firestore
- We need to manually sync these accounts using Firebase Console

## Current Implementation

We've already implemented multiple safeguards in our registration process:
- Retry mechanism (up to 5 attempts with exponential backoff)
- Batch operations instead of direct writes
- Document existence verification
- Error handling with user cleanup
- Delay between attempts

Sample of our problematic code:
```javascript
// Attempt to create Firestore document with multiple retries
let success = false;
let attempts = 0;

while (!success && attempts < 5) {
try {
attempts++;
// Batch operation attempt
const batch = writeBatch(db);
batch.set(doc(db, 'users', user.uid), userDocData);
await batch.commit();

// Verification with delay
const delayMs = 2000 * attempts;
await new Promise(resolve => setTimeout(resolve, delayMs));

// Check if document was created
const checkDoc = await getDoc(doc(db, 'users', user.uid));
if (checkDoc.exists()) {
success = true;
}
} catch (error) {
console.error(`Firestore error on attempt ${attempts}:`, error);
await new Promise(resolve => setTimeout(resolve, 1500 * attempts));
}
}
```

## Requirements

We need a developer to:
1. Analyze our code and identify why the Firestore document creation fails 50% of the time
2. Implement and test a solution on your own Firebase account to verify it works reliably
3. Provide a complete, ready-to-implement fix that guarantees synchronization

## Budget and Timeline

- Budget: $50 USD
- Timeline: Urgent - need solution within 3 days
- Deliverable: Complete code solution that achieves 100% reliability in user registration

## Preferred Solutions

We're open to either approach:

### Option 1: Cloud Functions Approach
Create a Firebase Cloud Function that triggers on Authentication user creation and ensures a Firestore document is created.

### Option 2: Client-Side Robust Implementation
Completely overhaul the registration process with bulletproof safeguards.

The solution must work across all browsers and devices, and should not require extensive maintenance. We prefer to stay within Firebase's free tier if possible.

Please only bid if you're confident you can solve this intermittent synchronization issue.