feat: harden support, localize knowledge and add operator availability [skip ci]

Source-only publication of reviewed commit 64e96a7f423673dc29ad56485be9fc79bce8af1c.

Passed in isolation: focused frontend/backend tests, race checks, TypeScript typecheck, lint, Go compilation, Flowgram build, and deterministic SDK build/tests.

Not accepted as a production release: Next.js export/native assembly remains blocked by environment memory limits; browser interaction and MySQL staging acceptance remain unverified. No production server, database/schema, runtime configuration, deployment, release tag, or workflow execution was performed.

Expected source tree: 0a4a7528e9.

web/components/support-chat/chat-shell.tsx

@@ -1,4 +1,4 @@
-// Modified for targeted chat realtime recovery; see docs/fixes/chat-realtime-recovery.md.
+// Modified for hardening and realtime recovery; see docs/hardening/README.md and docs/fixes/chat-realtime-recovery.md.
 "use client"
 
 import {
@@ -20,6 +20,7 @@ import { useShallow } from "zustand/react/shallow"
 
 import { SupportChatErrorBoundary } from "@/components/support-chat/chat-error-boundary"
 import { SupportChatConnectionStatus } from "@/components/support-chat/connection-status"
+import { PublicSupportAvailability } from "@/components/support-availability/public-status"
 import { SupportChatConversationSwitcher } from "@/components/support-chat/conversation-switcher"
 import { SupportChatNewRequestDialog } from "@/components/support-chat/new-request-dialog"
 import { getStandaloneClosedUrl } from "@/components/support-chat/close-navigation"
@@ -114,12 +115,14 @@ function SupportChatPanelContent() {
   useSupportChatSystemTheme()
 
   const messageListRef = useRef<SupportChatMessageListHandle | null>(null)
+  const mountedRef = useRef(false)
   const [isEmbedded, setIsEmbedded] = useState(false)
   const [isCloseDialogOpen, setIsCloseDialogOpen] = useState(false)
   const [isClosingConversation, setIsClosingConversation] = useState(false)
   const [isNewRequestDialogOpen, setIsNewRequestDialogOpen] = useState(false)
 
   const {
+    identityScope,
     title,
     subtitle,
     themeColor,
@@ -130,6 +133,8 @@ function SupportChatPanelContent() {
     loadOlderMessages,
     status,
     error,
+    sending,
+    uploadingAsset,
     isOpen,
     isVisible,
     setIsOpen,
@@ -146,6 +151,7 @@ function SupportChatPanelContent() {
     setConversationSatisfaction,
   } = useSupportChatStore(
     useShallow((state) => ({
+      identityScope: state.identityScope,
       title: state.title,
       subtitle: state.subtitle,
       themeColor: state.themeColor,
@@ -156,6 +162,8 @@ function SupportChatPanelContent() {
       loadOlderMessages: state.loadOlderMessages,
       status: state.status,
       error: state.error,
+      sending: state.sending,
+      uploadingAsset: state.uploadingAsset,
       isOpen: state.isOpen,
       isVisible: state.isVisible,
       setIsOpen: state.setIsOpen,
@@ -185,17 +193,18 @@ function SupportChatPanelContent() {
     if (document.visibilityState !== "visible") {
       return
     }
+    if (useSupportChatStore.getState().conversation?.id !== conversation.id) return
     void markConversationRead().catch((readError) => {
       console.error("Failed to mark support chat conversation read", readError)
     })
-  }, [conversation?.id, isVisible, markConversationRead])
+  }, [conversation, isVisible, markConversationRead])
 
   useEffect(() => {
     return bindSupportHostBridge({
       onInit: () => {
-        if (useSupportChatStore.getState().isOpen) {
-          bootstrap()
-        }
+        // Clear a previous visitor's private state even while the host keeps
+        // this frame hidden; visibility must never race identity replacement.
+        void bootstrap()
       },
       onOpen: () => {
         setIsOpen(true)
@@ -208,10 +217,16 @@ function SupportChatPanelContent() {
   }, [bootstrap, setIsOpen, setIsVisible])
 
   useEffect(() => {
-    bootstrap()
+    void bootstrap()
   }, [isOpen, bootstrap])
 
-  useEffect(() => () => disconnectSocket(), [disconnectSocket])
+  useEffect(() => {
+    mountedRef.current = true
+    return () => {
+      mountedRef.current = false
+      disconnectSocket()
+    }
+  }, [disconnectSocket])
 
   useEffect(() => {
     maybeMarkConversationRead()
@@ -239,9 +254,21 @@ function SupportChatPanelContent() {
     }
   }, [maybeMarkConversationRead, recoverConnection])
 
+  function requireDisplayedConversation() {
+    const current = useSupportChatStore.getState()
+    if (!conversation?.id || current.identityScope !== identityScope || current.conversation?.id !== conversation.id) {
+      throw new Error(t("supportChat.sendUnavailable"))
+    }
+  }
+
   async function handleSend(content: string) {
+    requireDisplayedConversation()
+    const submittedConversationId = conversation?.id
     await handleSendMessage(content)
-    messageListRef.current?.scrollToBottom()
+    const current = useSupportChatStore.getState()
+    if (current.identityScope === identityScope && current.conversation?.id === submittedConversationId) {
+      messageListRef.current?.scrollToBottom()
+    }
   }
 
   function handleCloseWindow() {
@@ -249,7 +276,8 @@ function SupportChatPanelContent() {
     if (isEmbedded) {
       requestSupportHostMinimize()
     } else {
-      window.location.replace(getStandaloneClosedUrl())
+      setIsOpen(false)
+      window.location.replace(getStandaloneClosedUrl(window.location.search))
     }
   }
 
@@ -260,6 +288,7 @@ function SupportChatPanelContent() {
     setIsClosingConversation(true)
     try {
       if (conversation?.id) {
+        requireDisplayedConversation()
         await closeConversation()
       }
       setIsCloseDialogOpen(false)
@@ -335,6 +364,8 @@ function SupportChatPanelContent() {
               </WindowActionButton>
             </div>
           </div>
+          <div className="mt-2"><SupportChatConnectionStatus status={status} /></div>
+          <PublicSupportAvailability identityScope={identityScope} />
         </header>
 
         <div className="grid min-h-0 flex-1 grid-rows-[minmax(0,1fr)_auto] overflow-hidden bg-muted/60 dark:bg-muted/30">
@@ -354,15 +385,29 @@ function SupportChatPanelContent() {
                   conversationId={conversation.id}
                   customerToken={getCustomerSessionToken()}
                   initialSatisfaction={conversation.satisfaction}
-                  onSubmitted={setConversationSatisfaction}
+                  onSubmitted={(satisfaction) => {
+                    if (mountedRef.current && useSupportChatStore.getState().identityScope === identityScope) {
+                      setConversationSatisfaction(satisfaction)
+                    }
+                  }}
                 />
               </div>
             ) : null}
             <CustomerMessageEditor
+              conversationId={conversation?.id}
+              draftScope={identityScope}
+              sending={sending}
+              uploadingAsset={uploadingAsset}
               disabled={!conversation || conversation.status === 4}
               onSend={handleSend}
-              onUploadImage={uploadMessageImage}
-              onSendAttachment={sendAttachment}
+              onUploadImage={async (file) => {
+                requireDisplayedConversation()
+                return uploadMessageImage(file)
+              }}
+              onSendAttachment={async (file) => {
+                requireDisplayedConversation()
+                await sendAttachment(file)
+              }}
             />
           </div>
         </div>