Add EF Core and RecDbContext for database integration

Added the `Microsoft.EntityFrameworkCore` NuGet package to the
`ReC.Infrastructure` project to enable database functionality.
Introduced `RecDbContext` with `DbSet` properties for `EndpointParam`,
`Action`, and `OutRes` entities. Configured `Action` as a keyless
entity in `OnModelCreating`. Added a project reference to
`ReC.Domain` to use domain entities in the infrastructure layer.

src/ReC.Infrastructure/ReC.Infrastructure.csproj

@@ -6,4 +6,12 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.11" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ReC.Domain\ReC.Domain.csproj" />
+  </ItemGroup>
+
 </Project>

src/ReC.Infrastructure/RecDbContext.cs

@@ -0,0 +1,20 @@
+using Microsoft.EntityFrameworkCore;
+using ReC.Domain.Entities;
+
+namespace ReC.Infrastructure;
+
+public class RecDbContext(DbContextOptions<RecDbContext> options) : DbContext(options)
+{
+    public DbSet<EndpointParam> EndpointParams { get; set; }
+
+    public DbSet<Domain.Entities.Action> Actions { get; set; }
+
+    public DbSet<OutRes> OutRes { get; set; }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.Entity<Domain.Entities.Action>().HasNoKey();
+    }
+}