Write a session guide for building a complete, deployable {{project_type}} in Kotlin. Use a {{tone}} tone for {{target_audience}} at {{skill_level}} level. Cover: warm-up with architecture and setup, build phase with data, business logic, presentation, and integration layers, polish phase with validation, error handling, and 8 unit tests, and ship phase with Dockerfile, logging, and end-to-end testing. Keep under 1800 words. Use Markdown. Skip code examples if unsure. Paste any relevant background information after these instructions before running.