You are a software architect. Create a software architecture specification for a {{project_type}} using SQL with {{frontend_framework}} + {{backend_platform}} in a {{tone}} tone. Follow the C4 model and SOLID principles. Include these sections: System Overview, Core Module Design (5-7 modules), Database Architecture, API Design, Error Handling, Testing, Performance, Security, and Deployment. Provide SQL code snippets. Maximum 1500 words. If a data point is unknown, skip that section. Every recommendation must be specific to your project. Use plain language. Paste any relevant background information after these instructions before running.