feat: add reply/forward/pin message flow across backend and web

- add reply_to/forwarded_from message fields and chat pinned_message field

- add forward and pin APIs plus reply support in message create

- wire web actions: Reply, Fwd, Pin and reply composer state

- fix spam policy bug: allow repeated identical messages, keep rate limiting

web/src/api/chats.ts

@@ -51,13 +51,15 @@ export async function sendMessageWithClientId(
   chatId: number,
   text: string,
   type: MessageType,
-  clientMessageId: string
+  clientMessageId: string,
+  replyToMessageId?: number
 ): Promise<Message> {
   const { data } = await http.post<Message>("/messages", {
     chat_id: chatId,
     text,
     type,
-    client_message_id: clientMessageId
+    client_message_id: clientMessageId,
+    reply_to_message_id: replyToMessageId
   });
   return data;
 }
@@ -116,3 +118,17 @@ export async function updateMessageStatus(
     status
   });
 }
+
+export async function forwardMessage(messageId: number, targetChatId: number): Promise<Message> {
+  const { data } = await http.post<Message>(`/messages/${messageId}/forward`, {
+    target_chat_id: targetChatId
+  });
+  return data;
+}
+
+export async function pinMessage(chatId: number, messageId: number | null): Promise<Chat> {
+  const { data } = await http.post<Chat>(`/chats/${chatId}/pin`, {
+    message_id: messageId
+  });
+  return data;
+}