Refactor error handling in Bumper, Media, Group, and Junction components to include contextual information

Updated error definitions in BumperErrors, MediaErrors, GroupErrors, and TemplateErrors to accept a parameter for contextual information, enhancing the clarity of error messages. Refactored related command handlers to utilize these updated error messages, ensuring that users receive specific details about the usage context when attempting to delete resources. Adjusted unit tests to verify the correctness of the new error handling logic.

backend/tests/TeleWave.Application.Tests/Programming/JunctionHandlersTests.cs

@@ -156,7 +156,7 @@ public class JunctionHandlersTests
                 new DeleteJunctionCommand(junctionId),
                 CancellationToken.None
             );
-            Assert.Equal(TemplateErrors.JunctionInUse, used.Error);
+            Assert.Equal(TemplateErrors.JunctionInUse(string.Empty).Code, used.Error.Code);
         }
 
         // Снимаем ссылку слота, но оставляем стыком по умолчанию — удалять всё равно нельзя.
@@ -189,7 +189,7 @@ public class JunctionHandlersTests
                 new DeleteJunctionCommand(junctionId),
                 CancellationToken.None
             );
-            Assert.Equal(TemplateErrors.JunctionInUse, asDefault.Error);
+            Assert.Equal(TemplateErrors.JunctionInUse(string.Empty).Code, asDefault.Error.Code);
         }
     }