Fix createdAt and expiresAt returning numbers instead of Date objects

setUTCMilliseconds() returns a numeric timestamp, not a Date object,
causing type mismatches and crashes on Android. Replace with new Date()
constructor which correctly creates Date objects from millisecond
timestamps. Also removes the downstream typeof workaround in
defaultDateMapper and the @ts-ignore suppression.

Fixes #581

https://claude.ai/code/session_016EHrcqQDgexLB5xApCxrZj

Author: claude

src/inApp/classes/IterableInAppMessage.ts

@@ -175,16 +175,8 @@ export class IterableInAppMessage {
     const campaignId = dict.campaignId;
     const trigger = IterableInAppTrigger.fromDict(dict.trigger);
 
-    let createdAt = dict.createdAt;
-    if (createdAt) {
-      const dateObject = new Date(0);
-      createdAt = dateObject.setUTCMilliseconds(createdAt);
-    }
-    let expiresAt = dict.expiresAt;
-    if (expiresAt) {
-      const dateObject = new Date(0);
-      expiresAt = dateObject.setUTCMilliseconds(expiresAt);
-    }
+    const createdAt = dict.createdAt ? new Date(dict.createdAt) : undefined;
+    const expiresAt = dict.expiresAt ? new Date(dict.expiresAt) : undefined;
     const saveToInbox = IterableUtil.readBoolean(dict, 'saveToInbox');
     const inboxMetadataDict = dict.inboxMetadata;
     let inboxMetadata: IterableInboxMetadata | undefined;
@@ -202,10 +194,6 @@ export class IterableInAppMessage {
       messageId,
       campaignId,
       trigger,
-      // MOB-10426: Speak to the team about `IterableInAppMessage` requiring a date
-      // object, but being passed a number in this case
-      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-      //  @ts-ignore
       createdAt,
       expiresAt,
       saveToInbox,

src/inbox/classes/IterableInboxDataModel.ts

@@ -211,15 +211,7 @@ export class IterableInboxDataModel {
       return '';
     }
 
-    let createdAt;
-
-    if (typeof message.createdAt === 'string') {
-      createdAt = new Date(parseInt(message.createdAt, 10));
-    } else {
-      createdAt = new Date(message.createdAt);
-    }
-
-    const defaultDateString = `${createdAt.toLocaleDateString()} at ${createdAt.toLocaleTimeString()}`;
+    const defaultDateString = `${message.createdAt.toLocaleDateString()} at ${message.createdAt.toLocaleTimeString()}`;
 
     return defaultDateString;
   }