feat(chat): add image messages and enforce readonly sessions

store/chat.ts

@@ -14,6 +14,7 @@ interface ChatState {
   messages: ChatMessage[]
   ensureOrderSession: (order: Order) => ChatSession
   sendTextMessage: (sessionId: string, sender: Sender, content: string) => void
+  sendImageMessage: (sessionId: string, sender: Sender, imageUrl: string) => void
 }
 
 function resolveAvatar(userId: string) {
@@ -74,6 +75,8 @@ export const useChatStore = create<ChatState>((set, get) => ({
   sendTextMessage: (sessionId, sender, content) => {
     const text = content.trim()
     if (!text) return
+    const session = get().sessions.find((item) => item.id === sessionId)
+    if (!session || session.readonly) return
 
     const now = new Date().toISOString()
     const message: ChatMessage = {
@@ -100,4 +103,35 @@ export const useChatStore = create<ChatState>((set, get) => ({
       ),
     }))
   },
+  sendImageMessage: (sessionId, sender, imageUrl) => {
+    const content = imageUrl.trim()
+    if (!content) return
+    const session = get().sessions.find((item) => item.id === sessionId)
+    if (!session || session.readonly) return
+
+    const now = new Date().toISOString()
+    const message: ChatMessage = {
+      id: generateId("msg"),
+      sessionId,
+      senderId: sender.id,
+      senderName: sender.name,
+      senderAvatar: sender.avatar,
+      type: "image",
+      content,
+      createdAt: now,
+    }
+
+    set((state) => ({
+      messages: [...state.messages, message],
+      sessions: state.sessions.map((item) =>
+        item.id === sessionId
+          ? {
+              ...item,
+              lastMessage: "[图片]",
+              lastMessageAt: now,
+            }
+          : item,
+      ),
+    }))
+  },
 }))