Refactor DbContext and add IRecDbContext interface

Refactored `DependencyInjection` to use a generic `TRecDbContext`
for flexibility and added scoped registration for `IRecDbContext`.
Updated `RecDbContext` to implement the new `IRecDbContext`
interface, ensuring adherence to the application-layer contract.

Introduced the `IRecDbContext` interface in the application layer,
defining `DbSet` properties for key entities and a `SaveChangesAsync`
method. Updated `ReC.Infrastructure.csproj` to reference the
application project for interface access.

src/ReC.Application/Common/Interfaces/IRecDbContext.cs

@@ -0,0 +1,19 @@
+using Microsoft.EntityFrameworkCore;
+using ReC.Domain.Entities;
+
+namespace ReC.Application.Common.Interfaces;
+
+public interface IRecDbContext
+{
+    public DbSet<EndpointParam> EndpointParams { get; }
+
+    public DbSet<RecAction> Actions { get; }
+
+    public DbSet<OutRes> OutRes { get; }
+
+    public DbSet<HeaderQueryResult> HeaderQueryResults { get; }
+
+    public DbSet<BodyQueryResult> BodyQueryResults { get; }
+
+    public Task<int> SaveChangesAsync(CancellationToken cancel = default);
+}