Add LLM digest setup and share timestamp context

lib/features/share_intake/domain/share_models.dart

@@ -38,6 +38,7 @@ class SharedPayload {
     required this.createdAt,
     required this.receivedAt,
     required this.platform,
+    this.sharedMessageDateTime,
     this.url,
     this.sourceDisplayName,
     this.sourceUserId,
@@ -53,6 +54,7 @@ class SharedPayload {
   final String? url;
   final DateTime createdAt;
   final DateTime receivedAt;
+  final DateTime? sharedMessageDateTime;
   final String platform;
   final String? sourceDisplayName;
   final String? sourceUserId;
@@ -68,6 +70,7 @@ class SharedPayload {
     String? url,
     DateTime? createdAt,
     DateTime? receivedAt,
+    DateTime? sharedMessageDateTime,
     String? platform,
     String? sourceDisplayName,
     String? sourceUserId,
@@ -83,6 +86,8 @@ class SharedPayload {
       url: url ?? this.url,
       createdAt: createdAt ?? this.createdAt,
       receivedAt: receivedAt ?? this.receivedAt,
+      sharedMessageDateTime:
+          sharedMessageDateTime ?? this.sharedMessageDateTime,
       platform: platform ?? this.platform,
       sourceDisplayName: sourceDisplayName ?? this.sourceDisplayName,
       sourceUserId: sourceUserId ?? this.sourceUserId,
@@ -101,6 +106,7 @@ class SharedPayload {
       'url': url,
       'createdAt': createdAt.toUtc().toIso8601String(),
       'receivedAt': receivedAt.toUtc().toIso8601String(),
+      'sharedMessageDateTime': sharedMessageDateTime?.toUtc().toIso8601String(),
       'platform': platform,
       'sourceDisplayName': sourceDisplayName,
       'sourceUserId': sourceUserId,
@@ -130,6 +136,9 @@ class SharedPayload {
         json['receivedAt'] as String? ??
             DateTime.now().toUtc().toIso8601String(),
       ).toLocal(),
+      sharedMessageDateTime: json['sharedMessageDateTime'] == null
+          ? null
+          : DateTime.parse(json['sharedMessageDateTime'] as String).toLocal(),
       platform: json['platform'] as String? ?? 'unknown',
       sourceDisplayName: json['sourceDisplayName'] as String?,
       sourceUserId: json['sourceUserId'] as String?,
@@ -244,7 +253,8 @@ class SharedMessageEntry {
 
   String get sourceApp => payload.sourceApp;
   String get messageText => payload.rawText;
-  DateTime get sharedAt => payload.createdAt;
+  DateTime get sharedAt => payload.sharedMessageDateTime ?? payload.createdAt;
+  DateTime? get sharedMessageDateTime => payload.sharedMessageDateTime;
   SharedPayloadType get payloadType => payload.payloadType;
   String? get url => payload.url;
   String? get sourceDisplayName => payload.sourceDisplayName;