fix: recover chat replies and organize setup navigation [skip ci]

Targeted source-only patch from reviewed local e370485. Adds bounded realtime/catch-up recovery and moves the setup wizard under System. Static checks only; regression tests, full build and runtime verification have not been run. No deployment. Separate hardening-review branch is not merged. Expected tree: 6235478b9a.

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

@@ -1,3 +1,4 @@
+// Modified for targeted chat realtime recovery; see docs/fixes/chat-realtime-recovery.md.
 "use client"
 
 import {
@@ -139,6 +140,7 @@ function SupportChatPanelContent() {
     sendAttachment,
     retry,
     disconnectSocket,
+    recoverConnection,
     markConversationRead,
     closeConversation,
     setConversationSatisfaction,
@@ -164,6 +166,7 @@ function SupportChatPanelContent() {
       sendAttachment: state.sendAttachment,
       retry: state.retry,
       disconnectSocket: state.disconnectSocket,
+      recoverConnection: state.recoverConnection,
       markConversationRead: state.markConversationRead,
       closeConversation: state.closeConversation,
       setConversationSatisfaction: state.setConversationSatisfaction,
@@ -206,13 +209,9 @@ function SupportChatPanelContent() {
 
   useEffect(() => {
     bootstrap()
+  }, [isOpen, bootstrap])
 
-    return () => {
-      if (!isOpen) {
-        disconnectSocket()
-      }
-    }
-  }, [isOpen, bootstrap, disconnectSocket])
+  useEffect(() => () => disconnectSocket(), [disconnectSocket])
 
   useEffect(() => {
     maybeMarkConversationRead()
@@ -220,21 +219,25 @@ function SupportChatPanelContent() {
 
   useEffect(() => {
     const handleVisibilityChange = () => {
+      recoverConnection()
       if (document.visibilityState === "visible") {
         maybeMarkConversationRead()
       }
     }
     const handleFocus = () => {
+      recoverConnection()
       maybeMarkConversationRead()
     }
 
     document.addEventListener("visibilitychange", handleVisibilityChange)
     window.addEventListener("focus", handleFocus)
+    window.addEventListener("online", recoverConnection)
     return () => {
       document.removeEventListener("visibilitychange", handleVisibilityChange)
       window.removeEventListener("focus", handleFocus)
+      window.removeEventListener("online", recoverConnection)
     }
-  }, [maybeMarkConversationRead])
+  }, [maybeMarkConversationRead, recoverConnection])
 
   async function handleSend(content: string) {
     await handleSendMessage(content)