Problem

TheIEntityTypeConfiguration files were placed in/Infrastructure/Persistence/Configurations/ instead of being co-located with their related features in theFeatures/ directory. This violated the vertical slice architecture principle of keeping all related code together by feature rather than separating by technical concerns.

Solution

Moved the Entity Framework Core configuration files to their respective feature folders:

• TodoItemConfiguration.cs →Features/TodoItems/TodoItemConfiguration.cs
• TodoListConfiguration.cs →Features/TodoLists/TodoListConfiguration.cs

Updated the namespaces to match their new feature-specific locations and removed the now-empty/Configurations/ directory.

Why This Improves the Architecture

Before: Developers working on TodoItem features had to navigate between/Features/TodoItems/ for business logic and/Infrastructure/Persistence/Configurations/ for database configuration.

After: All TodoItem-related code (controllers, commands, handlers, validators, domain events, and EF configuration) now lives together inFeatures/TodoItems/.

This change aligns with the project's stated goal from the README:

The goal is to stop thinking about horizontal layers and start thinking about vertical slices and organize code byFeatures. When the code is organized by feature you get the benefits of not having to jump around projects, folders, and files. Things related to given features are placed close together.

Technical Verification

• ✅ EF Core'sApplyConfigurationsFromAssembly() automatically discovers configurations regardless of their location in the assembly
• ✅ All existing tests pass + added new tests to verify configurations are still applied correctly
• ✅ Application builds and runs successfully with proper database schema constraints
• ✅ No breaking changes to existing functionality

The move demonstrates that infrastructure concerns can and should be organized by feature when they are feature-specific, rather than being artificially separated into technical layers.

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