✨ ActivityPub service impl basis

lib/models/activitypub.dart

@@ -0,0 +1,65 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'activitypub.freezed.dart';
+part 'activitypub.g.dart';
+
+@freezed
+sealed class SnActivityPubUser with _$SnActivityPubUser {
+  const factory SnActivityPubUser({
+    required String actorUri,
+    required String username,
+    required String displayName,
+    required String bio,
+    required String avatarUrl,
+    required DateTime followedAt,
+    required bool isLocal,
+    required String instanceDomain,
+  }) = _SnActivityPubUser;
+
+  factory SnActivityPubUser.fromJson(Map<String, dynamic> json) =>
+      _$SnActivityPubUserFromJson(json);
+}
+
+@freezed
+sealed class SnActivityPubActor with _$SnActivityPubActor {
+  const factory SnActivityPubActor({
+    required String id,
+    @Default('') String type,
+    String? displayName,
+    String? username,
+    String? summary,
+    String? inboxUri,
+    String? outboxUri,
+    String? followersUri,
+    String? followingUri,
+    String? featuredUri,
+    String? icon,
+    String? image,
+    String? publicKeyId,
+    String? publicKey,
+    @Default(false) bool isBot,
+    @Default(false) bool isLocked,
+    @Default(true) bool discoverable,
+    @Default(false) bool manuallyApprovesFollowers,
+    Map<String, dynamic>? endpoints,
+    Map<String, dynamic>? publicKeyData,
+    Map<String, dynamic>? metadata,
+    DateTime? lastFetchedAt,
+    DateTime? lastActivityAt,
+  }) = _SnActivityPubActor;
+
+  factory SnActivityPubActor.fromJson(Map<String, dynamic> json) =>
+      _$SnActivityPubActorFromJson(json);
+}
+
+@freezed
+sealed class SnActivityPubFollowResponse with _$SnActivityPubFollowResponse {
+  const factory SnActivityPubFollowResponse({
+    required bool success,
+    required String message,
+    required String targetActorUri,
+  }) = _SnActivityPubFollowResponse;
+
+  factory SnActivityPubFollowResponse.fromJson(Map<String, dynamic> json) =>
+      _$SnActivityPubFollowResponseFromJson(json);
+}