Sync was blocked because the migration registry table creation required
CREATE TABLE permissions that the database user might not have.
Changes:
- Check if migration registry tables exist before attempting to create them
- Skip creation if table exists and user lacks CREATE permissions
- Use information_schema to reliably check table existence
- Apply same fix to user sync status table creation
- Gracefully handle ALTER TABLE failures for backward compatibility
This allows sync to proceed even if the client is a read-limited database user,
as long as the required tables have already been created by an administrator.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
