Migrate error log to batched logging system

## Objective

Migrate error log creation from direct DB writes to the batched logging system.

## Implementation Details

### Repository Changes

1. **Update** `ErrorLogDBSource`
- Add `bulk_create()` method using `BulkCreator`
- Keep existing `create()` for backward compatibility
1. **Update** `ErrorLogRepository`
- Route `create()` calls to queue manager
- Add `flush()` method

### Service Changes

1. **Update** `ErrorLogService`
- Change `create()` to enqueue
- Return immediately

### Configuration

- Batch size: 100 (default)
- Flush interval: 5 seconds
- Redis backup: disabled (not critical)

## Testing

- Test error log enqueueing
- Test batch creation
- Integration tests

## Acceptance Criteria

- Error logs written in batches
- No functional regression
- Reduced DB load
- All tests passing

JIRA Issue: BA-4235