Database Schema Designer

Design a normalized database schema for [APPLICATION TYPE].

Features to support: [LIST MAIN FEATURES]
Expected scale: [ROWS/DAY]
Database: [PostgreSQL/MySQL/MongoDB]

Provide:
- Entity relationship diagram (text-based)
- CREATE TABLE statements with proper types
- Primary and foreign key constraints
- Indexes for common queries
- Enum types for status fields
- Soft delete pattern
- Audit columns (created_at, updated_at)
- Notes on normalization decisions