refactor(repository): add query parameter to IRepository.Where and constrain IRepository.Entity

- Updated `IRepository<TEntity>.Where()` to accept an `Expression<Func<TEntity, bool>>` for filtering.
- Added `where TEntity : IEntity` constraint to `IRepository.Entity<TEntity>()` method.
- No functional logic changes, only interface refactoring for stronger typing and query support.

DigitalData.Core.Abstraction.Application/Repository/IRepository.cs

@@ -11,7 +11,7 @@ public interface IRepository<TEntity>
 
     public Task<IEnumerable<TEntity>> CreateAsync(IEnumerable<TEntity> entities, CancellationToken cancel = default);
 
-    public IQueryable<TEntity> Where();
+    public IQueryable<TEntity> Where(Expression<Func<TEntity, bool>> expression);
 
     public IQueryable<TEntity> Get();
 
@@ -34,5 +34,5 @@ public interface IRepository<TEntity>
 
 public interface IRepository
 {
-    public IRepository<TEntity> Entity<TEntity>();
+    public IRepository<TEntity> Entity<TEntity>() where TEntity : IEntity;
 }