ios: reconnect servers when network changes

iOS does not report the sockets of the previous network as broken, so
after switching between Wi-Fi and mobile the agent keeps using dead
sessions - setting network info does not drop them. Recovery only
happened when the OS finally failed the socket, via TCP keep-alive or
the SMP ping monitor, taking from ~90 seconds to tens of minutes.

Reconnect the servers on every network change after the first one, when
the network is online. Changes that keep the same network type, e.g.
switching between Wi-Fi networks, are not detected, as network info only
has the network type.

apps/ios/Shared/Model/NetworkObserver.swift

@@ -35,8 +35,12 @@ class NetworkObserver {
             online: path.status == .satisfied
         )
         if (prevInfo != info) {
+            // iOS does not report the sockets of the previous network as broken, so the servers have to
+            // be reconnected. There is nothing to reconnect before the first network info is set.
+            let shouldReconnect = prevInfo != nil && info.online
             prevInfo = info
             setNetworkInfo(info)
+            if shouldReconnect { reconnectServers() }
         }
     }
 
@@ -70,4 +74,15 @@ class NetworkObserver {
             }
         }
     }
+
+    private func reconnectServers() {
+        Task {
+            if !hasChatCtrl() { return }
+            do {
+                try await reconnectAllServers()
+            } catch let err {
+                logger.error("reconnectAllServers error: \(responseError(err))")
+            }
+        }
+    }
 }