feat(api,core,infra): refactor endpoint routing and add institution account discovery

- Move login and refresh endpoints under a unified /auth route group
- Relocate institution connection logic from /accounts to /institutions
- Implement GET /institutions/{id}/available to fetch real-time Plaid
accounts
- Introduce HttpRequestBuilder utility to streamline integration testing
- Enhance PlaidService with GetAccountsAsync to support account fetching
- Clean up global usings and project structure for better domain
isolation

src/FiscalOS.API/Accounts/AccountsExtensions.cs

@@ -10,7 +10,6 @@ internal static class AccountsExtensions
       .RequireAuthorization();
 
     accountsGroup.MapAddEndpoint();
-    accountsGroup.MapConnectEndpoint();
 
     return accountsGroup;
   }

src/FiscalOS.API/Accounts/Add/Endpoint.cs

@@ -1,5 +1,3 @@
-using FiscalOS.Core.Accounts;
-
 namespace FiscalOS.API.Accounts.Add;
 
 internal static class Endpoint

src/FiscalOS.API/Accounts/Add/Request.cs

@@ -1,4 +1,3 @@
-
 namespace FiscalOS.API.Accounts.Add;
 
 public record Request : IValidatableObject

src/FiscalOS.API/Accounts/Connect/Endpoint.cs

@@ -1,59 +0,0 @@
-using FiscalOS.Core.Accounts;
-
-namespace FiscalOS.API.Accounts.Connect;
-
-internal static class Endpoint
-{
-  private const string Route = "/connect";
-
-  public static RouteHandlerBuilder MapConnectEndpoint(this RouteGroupBuilder groupBuilder)
-  {
-    return groupBuilder.MapPost(Route, HandleAsync);
-  }
-
-  private static async Task<IResult> HandleAsync(
-    HttpContext httpContext,
-    [FromBody] Request request,
-    [FromServices] AppDbContext appDbContext,
-    [FromServices] PlaidService plaidService,
-    [FromServices] IEncryptor encryptor,
-    CancellationToken ct
-  )
-  {
-    var userId = httpContext.GetUserId();
-
-    var user = await appDbContext.Users
-      .Include(u => u.Institutions
-        .Where(
-          i => i.Metadata is PlaidMetadata &&
-            ((PlaidMetadata)i.Metadata).PlaidId == request.PlaidInstitutionId
-        )
-      )
-      .ThenInclude(i => i.Metadata)
-      .SingleOrDefaultAsync(u => u.Id == userId, ct);
-
-    if (user is null)
-    {
-      return Results.Unauthorized();
-    }
-
-    if (user.Institutions.Any())
-    {
-      return Results.Conflict();
-    }
-
-    var (itemId, accessToken) = await plaidService.ExchangeTokenAsync(request.PublicToken);
-    var item = await plaidService.GetItemAsync(accessToken);
-
-    var encryptedAccessToken = await encryptor.EncryptAsyncFor(user, accessToken, ct);
-
-    var plaidMetadata = PlaidMetadata.From(item.InstitutionId, item.InstitutionName, encryptedAccessToken);
-    var institution = Institution.From(item.InstitutionName, plaidMetadata);
-
-    user.AddInstitution(institution);
-
-    await appDbContext.SaveChangesAsync(ct);
-
-    return Results.Ok();
-  }
-}

src/FiscalOS.API/Accounts/Connect/Request.cs

@@ -1,22 +0,0 @@
-namespace FiscalOS.API.Accounts.Connect;
-
-public record Request : IValidatableObject
-{
-  public string PublicToken { get; init; } = string.Empty;
-  public string PlaidInstitutionId { get; init; } = string.Empty;
-
-  public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
-  {
-    if (string.IsNullOrWhiteSpace(PublicToken))
-    {
-      var fieldName = nameof(PublicToken);
-      yield return new($"The {fieldName} field is required.", [fieldName]);
-    }
-
-    if (string.IsNullOrWhiteSpace(PlaidInstitutionId))
-    {
-      var fieldName = nameof(PlaidInstitutionId);
-      yield return new($"The {fieldName} field is required.", [fieldName]);
-    }
-  }
-}