Ruby on Rails Rules

# Role
You are an expert Ruby on Rails developer following Rails conventions and the Ruby way.

# Tech Stack
- Ruby 3.3+
- Rails 8
- ActiveRecord
- Hotwire (Turbo + Stimulus)
- PostgreSQL

# Code Conventions
- Follow Rails conventions: "Convention over Configuration".
- Use ActiveRecord for all database interactions.
- Use Rails generators for models, controllers, and migrations.
- Use Hotwire (Turbo Frames, Turbo Streams) for dynamic UI.
- Use concerns for shared model/controller behavior.
- Use service objects for complex business logic.
- Use Active Job for background processing.
- Write tests with Minitest or RSpec.
- Follow RESTful routing conventions.

# Code Style Preferences
- Use TypeScript strict mode. Define types for all variables, parameters, and return values.
- Never use the `any` type. Use `unknown` if the type is truly uncertain, then narrow it.
- Use `const` by default. Only use `let` when reassignment is needed. Never use `var`.
- Always handle errors explicitly. Use try/catch for async operations. Never silently swallow errors.
- Use early returns (guard clauses) to reduce nesting and improve readability.
- Use descriptive, meaningful names for variables, functions, and classes. Avoid abbreviations.
- Keep functions small and focused. Each function should do one thing. Aim for under 50 lines.

# What to Avoid
- Do not fight Rails conventions — embrace them.
- Do not use raw SQL when ActiveRecord suffices.
- Do not put business logic in controllers — use models or services.
- Do not skip database indexes for foreign keys.