feat: add local-first private AI digest workflow

Migrate app code into canonical feature slices, add phone-only AI digest scheduling and review, wire local notification/background task support, and cover the flow with tests.

lib/features/share_intake/application/share_capture_models.dart

@@ -0,0 +1,60 @@
+class SharedMessageIngestInput {
+  const SharedMessageIngestInput({
+    required this.sourceApp,
+    required this.messageText,
+    this.sourceDisplayName,
+    this.sourceUserId,
+    this.sourceThreadId,
+    this.sharedAt,
+  });
+
+  final String sourceApp;
+  final String messageText;
+  final String? sourceDisplayName;
+  final String? sourceUserId;
+  final String? sourceThreadId;
+  final DateTime? sharedAt;
+}
+
+enum SharedMessageIngestStatus { imported, queuedForResolution }
+
+class SharedMessageIngestResult {
+  const SharedMessageIngestResult({
+    required this.status,
+    required this.createdProfile,
+    required this.createdSourceLink,
+    this.profileId,
+    this.profileName,
+    this.momentId,
+    this.inboxEntryId,
+  });
+
+  const SharedMessageIngestResult.imported({
+    required this.profileId,
+    required this.profileName,
+    required this.createdProfile,
+    required this.createdSourceLink,
+    required this.momentId,
+  }) : status = SharedMessageIngestStatus.imported,
+       inboxEntryId = null;
+
+  const SharedMessageIngestResult.queuedForResolution({
+    required this.inboxEntryId,
+  }) : status = SharedMessageIngestStatus.queuedForResolution,
+       createdProfile = false,
+       createdSourceLink = false,
+       profileId = null,
+       profileName = null,
+       momentId = null;
+
+  final SharedMessageIngestStatus status;
+  final String? profileId;
+  final String? profileName;
+  final bool createdProfile;
+  final bool createdSourceLink;
+  final String? momentId;
+  final String? inboxEntryId;
+
+  bool get isQueuedForResolution =>
+      status == SharedMessageIngestStatus.queuedForResolution;
+}