## ADDED Requirements

### Requirement: users.is_admin column
The `users` table SHALL include an `is_admin` boolean column, NOT NULL default FALSE, added idempotently.

#### Scenario: Fresh database
- **WHEN** `db/schema.sql` is applied to an empty database
- **THEN** `users.is_admin` exists defaulting to FALSE

#### Scenario: Existing database
- **WHEN** `db/schema.sql` is re-applied to an existing database
- **THEN** the column is added without error
