replace: swap prosappweb content for prosapp_web_app (more complete version)

prosapp_web_app has chat, dashboard, calendar, support, 13 providers and
Fluro URL routing. Keep Dockerfile + nginx.conf from previous prosappweb.
Upgrade google_fonts 6.2.1 → 8.1.0 (Dart 3.12 compat fix).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/models/message_entity.dart

@@ -0,0 +1,36 @@
+class MessageEntity {
+  final String ownerId;
+  final String content;
+  final DateTime createdAt;
+
+  const MessageEntity({
+    required this.ownerId,
+    required this.content,
+    required this.createdAt,
+  });
+
+  static MessageEntity fromDocument(Map<String, dynamic> doc) {
+    return MessageEntity(
+      ownerId: doc['owner_id'] as String,
+      content: doc['content'] as String,
+      createdAt: DateTime.parse(doc['created_at'] as String),
+    );
+  }
+
+  Map<String, dynamic> toDocument() {
+    return {
+      'owner_id': ownerId,
+      'content': content,
+      'created_at': createdAt.toIso8601String(),
+    };
+  }
+
+  @override
+  String toString() {
+    return '''MessageEntity{
+      ownerId: $ownerId, 
+      content: $content, 
+      createdAt: $createdAt
+      }''';
+  }
+}