Fix FastEndpoints/Swagger wiring and missing required fields in DTOs

- Register FastEndpoints, SwaggerDocument, DbContext in Program.cs
- Add DbContextOptions constructor to PyroFetesDbContext
- Add CityId to Show DTOs and endpoints (NOT NULL in DB)
- Add F4T2NumberApproval/F4T2ExpirationDate to Staff DTOs and endpoints
- Simplify DeleteShow to rely on DB cascade instead of manual includes
- Default NOT NULL string fields to empty string on create

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PyroFetes/Endpoints/Staff/CreateStaffEndpoint.cs

@@ -19,19 +19,23 @@ public class CreateStaffEndpoint(PyroFetesDbContext pf3DbContext):Endpoint<Creat
             FirstName = req.FirstName,
             LastName = req.LastName,
             Profession = req.Profession,
-            Email = req.Email
+            Email = req.Email,
+            F4T2NumberApproval = req.F4T2NumberApproval,
+            F4T2ExpirationDate = req.F4T2ExpirationDate
         };
-        
+
         pf3DbContext.Staffs.Add(staff);
         await pf3DbContext.SaveChangesAsync(ct);
-        
+
         var result = new ReadStaffDto()
         {
             Id = staff.Id,
-            FirstName = req.FirstName,
-            LastName = req.LastName,
-            Profession = req.Profession,
-            Email = req.Email
+            FirstName = staff.FirstName,
+            LastName = staff.LastName,
+            Profession = staff.Profession,
+            Email = staff.Email,
+            F4T2NumberApproval = staff.F4T2NumberApproval,
+            F4T2ExpirationDate = staff.F4T2ExpirationDate
         };
 
         await Send.OkAsync(result, ct);