SQL Query Generation

Act as a Database Administrator. Write a PostgreSQL query for the following request.

Schema Context:

• Table 'users' (id, email, signup_date)
• Table 'orders' (id, user_id, amount, status, created_at)

Goal: Find the top 10% of users by total spend (LTV) who signed up in the last 12 months, but haven't purchased anything in the last 30 days (churn risk).

Constraints:

• Use Common Table Expressions (CTEs) for readability.
• Exclude 'refunded' status orders.
• Format the output code for readability.