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/store/chatStore.ts

@@ -7,6 +7,7 @@ interface ChatState {
   activeChatId: number | null;
   messagesByChat: Record<number, Message[]>;
   typingByChat: Record<number, number[]>;
+  replyToByChat: Record<number, Message | null>;
   loadChats: (query?: string) => Promise<void>;
   setActiveChatId: (chatId: number | null) => void;
   loadMessages: (chatId: number) => Promise<void>;
@@ -22,6 +23,8 @@ interface ChatState {
   removeOptimisticMessage: (chatId: number, clientMessageId: string) => void;
   setMessageDeliveryStatus: (chatId: number, messageId: number, status: DeliveryStatus) => void;
   setTypingUsers: (chatId: number, userIds: number[]) => void;
+  setReplyToMessage: (chatId: number, message: Message | null) => void;
+  updateChatPinnedMessage: (chatId: number, pinnedMessageId: number | null) => void;
 }
 
 export const useChatStore = create<ChatState>((set, get) => ({
@@ -29,6 +32,7 @@ export const useChatStore = create<ChatState>((set, get) => ({
   activeChatId: null,
   messagesByChat: {},
   typingByChat: {},
+  replyToByChat: {},
   loadChats: async (query) => {
     const chats = await getChats(query);
     const currentActive = get().activeChatId;
@@ -134,5 +138,11 @@ export const useChatStore = create<ChatState>((set, get) => ({
     }));
   },
   setTypingUsers: (chatId, userIds) =>
-    set((state) => ({ typingByChat: { ...state.typingByChat, [chatId]: userIds } }))
+    set((state) => ({ typingByChat: { ...state.typingByChat, [chatId]: userIds } })),
+  setReplyToMessage: (chatId, message) =>
+    set((state) => ({ replyToByChat: { ...state.replyToByChat, [chatId]: message } })),
+  updateChatPinnedMessage: (chatId, pinnedMessageId) =>
+    set((state) => ({
+      chats: state.chats.map((chat) => (chat.id === chatId ? { ...chat, pinned_message_id: pinnedMessageId } : chat))
+    }))
 }));