wire: echo UDID in DataHeaders on every response

SignUpTask.Parse validates data_headers.udid against Certification.Udid;
mismatch discards the response. Sourced from the same mappedUdid the
translation middleware uses to decrypt — never controller state. Other
endpoints carry the extra key; SignUpTask is the only reader.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Middlewares/ShadowverseTranslationMiddleware.cs

@@ -166,7 +166,11 @@ public class ShadowverseTranslationMiddleware : IMiddleware
                 // populated (prod sends real numbers for the title check too, but 0 / 0 satisfies
                 // the client's BaseTask.Parse which only reads result_code + servertime here).
                 ShortUdid = viewer?.ShortUdid ?? 0,
-                ViewerId = viewer?.Id ?? 0
+                ViewerId = viewer?.Id ?? 0,
+                // Echo the decrypted-against UDID. Most clients ignore this field; SignUpTask.Parse
+                // requires it (validates against Certification.Udid on the response). Comes from
+                // mappedUdid (the value used for AES); never from controller state.
+                Udid = mappedUdid?.ToString() ?? ""
             }
         };