Add T-Beam WiFi button toggle

src/helpers/WiFiSetupPortal.cpp

@@ -321,6 +321,15 @@ bool WiFiSetupPortal::begin(const char* ap_name, SaveCallback save_callback, voi
   return true;
 }
 
+void WiFiSetupPortal::stop() {
+  _active = false;
+}
+
+bool WiFiSetupPortal::isStopping() const {
+  const PortalImpl* impl = static_cast<const PortalImpl*>(_impl);
+  return impl && impl->task != nullptr;
+}
+
 void WiFiSetupPortal::configureRecovery(const char* ssid, const char* password,
                                         uint32_t interval_ms,
                                         uint32_t initial_delay_ms) {

src/helpers/WiFiSetupPortal.h

@@ -14,6 +14,7 @@ public:
   // Starts an open setup AP and captive HTTP form. The AP remains available
   // after a failed association and shuts down shortly after a successful one.
   bool begin(const char* ap_name, SaveCallback save_callback, void* context);
+  void stop();
   // Retry interval is the steady-state cadence. initial_delay_ms defaults to
   // that interval, but callers that opened the portal partway through an
   // outage can preserve the original reconnect schedule with a shorter delay.
@@ -21,6 +22,7 @@ public:
                          uint32_t interval_ms, uint32_t initial_delay_ms = 0);
 
   bool isActive() const { return _active; }
+  bool isStopping() const;
   IPAddress apIP() const { return IPAddress(192, 168, 4, 1); }
 
   // Companion WiFi builds keep their runtime credentials in NVS.

src/helpers/esp32/SerialWifiInterface.cpp

@@ -7,6 +7,15 @@ void SerialWifiInterface::begin(int port) {
   server.begin(port);
 }
 
+void SerialWifiInterface::end() {
+  disable();
+  if (client) client.stop();
+  server.end();
+  deviceConnected = false;
+  resetReceivedFrameHeader();
+  clearBuffers();
+}
+
 // ---------- public methods
 void SerialWifiInterface::enable() { 
   if (_isEnabled) return;

src/helpers/esp32/SerialWifiInterface.h

@@ -45,6 +45,7 @@ public:
   }
 
   void begin(int port);
+  void end();
 
   // BaseSerialInterface methods
   void enable() override;