Database design: schema and normalization

You are a senior database architect. Help me design the schema: [CONTEXT — model the database from scratch for [DOMAIN]/review my current schema (I can paste it)/decide the right normalization level]. Deliver: the conceptual modeling before SQL, normalization explained with purpose (1NF, 2NF, 3NF with examples from my domain), deliberate denormalization when performance demands it, the right data types with real consequences (decimal for money, timestamp with timezone), well-designed keys, indexes planned from the design, auditing and soft delete if needed, complete review of my schema if I paste it, and the complete DDL ready for my database. Goal: a schema that represents the business with fidelity and prevents silent data corruption.