fix(admin): parse mission_change_time as wire datetime string

Real /load/index captures ship mission_meta.mission_change_time as a
"yyyy-MM-dd HH:mm:ss" string (see FriendService.DefaultMissionChangeTime for the
canonical game format) but ImportViewerRequest typed it as long? Unix seconds. The
FromUnixTimeSeconds branch had never been reachable with a real capture, and any
loader dump carrying mission_meta 400d the whole request. Change the DTO field to
string? and parse in the controller with DateTime.TryParseExact + invariant culture
(AssumeUniversal | AdjustToUniversal); unparseable values skip cleanly instead of
poisoning the whole viewer import.

Also fix is_received_two_pick_mission: DTO's JsonPropertyName was
has_received_pick_two_mission (never matched the wire key), and the wire ships "1"
/"0" strings not booleans. Rename to the actual wire key, retype to int?, controller
normalizes `hrptm != 0` before assigning to the bool DB property.

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

SVSim.EmulatedEntrypoint/Models/Dtos/Requests/Admin/ImportViewerRequest.cs

@@ -124,12 +124,18 @@ public class ImportStoryProgress
 
 public class ImportMissionMeta
 {
-    [JsonPropertyName("has_received_pick_two_mission")]
-    public bool? HasReceivedPickTwoMission { get; set; }
+    // Wire key is `is_received_two_pick_mission` (loader-captured verbatim from /load/index
+    // user_info); the field ships as a string "1"/"0" not a bool. Keep the DTO type as int?
+    // so binding matches; the controller normalizes to bool.
+    [JsonPropertyName("is_received_two_pick_mission")]
+    public int? HasReceivedPickTwoMission { get; set; }
 
     [JsonPropertyName("mission_receive_type")]
     public int? MissionReceiveType { get; set; }
 
+    // Wire ships this as a "yyyy-MM-dd HH:mm:ss" string, NOT a Unix long (see
+    // FriendService.DefaultMissionChangeTime for the canonical game format). Controller
+    // parses via DateTime.TryParseExact with invariant culture.
     [JsonPropertyName("mission_change_time")]
-    public long? MissionChangeTime { get; set; }
+    public string? MissionChangeTime { get; set; }
 }