Write a query to return every row in signups with its clean_email, matching customer_id from customers, and status.
Build clean_email by removing spaces, tabs, carriage returns and newlines from both ends of signups.email, then lowercasing it. Preserve NULL. Customer emails are already lowercase with no surrounding spaces; match the complete cleaned value by equality. Return NULL for customer_id when no customer matches.
Set status to invalid when the cleaned value is NULL or contains no @; otherwise use matched if a customer was found, or unmatched if none was found. Return each signup exactly once, including invalid and unmatched signups.
Ordering: Sort by signup_id in ascending order.