Network Type Transition Optimization

Nucleic-Session: 40F8C53A-F001-423A-8607-EAE181DBE14B
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/Models/RemoteStore.swift

@@ -265,10 +265,29 @@ final class RemoteStore: ObservableObject {
 
     func onAppear() {
         if demoMode { seedDemo(); return }
+        // Re-plan every connection the moment the network path changes (left Wi-Fi, joined a
+        // network, cellular⇄Wi-Fi) — the proactive half of "immediate switchover".
+        pathMonitor.onChange = { [weak self] in self?.handlePathChange() }
+        pathMonitor.start()
         discovery.start()
         if isPaired { reconnect() }
     }
 
+    /// A network-path change: tell each host connection to re-plan its transport now.
+    private func handlePathChange() {
+        guard !demoMode else { return }
+        for conn in connections.values { conn.networkPathChanged() }
+    }
+
+    /// Returning to the foreground: the network may have changed while the app was suspended (and
+    /// path/keepalive callbacks were frozen). Re-read the path and re-dial anything not live so the
+    /// transport is correct by the time the UI is on screen, rather than after a backoff.
+    func onForeground() {
+        guard !demoMode, isPaired else { return }
+        pathMonitor.refresh()
+        reconnect()
+    }
+
     private func seedDemo() {
         connectivity = .connected(.lan)
         hostName = "Andrew's Mac"