Database Schema Designer with Migrations

Design a database schema for [feature_description]. Requirements:
- Use PostgreSQL-compatible types (uuid, timestamptz, text, integer, jsonb)
- Primary key should be uuid with gen_random_uuid() default
- Include created_at and updated_at timestamptz columns with defaults
- Add proper foreign key constraints with ON DELETE behavior
- Create indexes for columns used in WHERE clauses and JOINs
- Add CHECK constraints for enum-like values
- Include Row Level Security (RLS) policies if using Supabase
- Write the migration as a .sql file
- Add a rollback migration (DOWN) as comments
- Include seed data examples as INSERT statements
- Consider soft delete (deleted_at) vs hard delete based on requirements
- Add comments on non-obvious columns