Fix inconsistent EF Core versions across projects

[coderabbitai]

Description

There's an inconsistency in the EF Core versions used across different projects:

• Migration snapshot in src/Api/Migrations/DatabaseContextModelSnapshot.cs uses EF Core 8.0.8
• src/Core/Core.csproj references EF Core 8.0.8
• src/Api/Api.csproj uses Microsoft.EntityFrameworkCore.Tools version 8.0.0

Action Required

Update all EF Core packages to use consistent versions (preferably 8.0.8) to ensure compatibility across all components and for all team members.

Background

This issue was identified during PR review: #8 (comment)