Add Matter Binding cluster support to MatterSwitch

Lets a Matter switch (opt-in via beginWithBinding()) be bound directly to
another device, e.g. a light, and control it without a hub relaying every
command - closes #101. Adds MatterBindingManager
to serve the Binding cluster's list attribute and dispatch bound OnOff
commands over CASE/group sessions, built entirely from SDK pieces already
available (BindingTable, CASESessionManager, CommandSender) since the
official bindings cluster server/BindingManager aren't vendored. Plain
begin() and the existing matter_switch/matter_lightbulb examples are
untouched; matter_switch_binding and matter_lightbulb_binding demonstrate
the new opt-in path.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: lboue

libraries/Matter/examples/matter_lightbulb_binding/matter_lightbulb_binding.ino

@@ -0,0 +1,91 @@
+/*
+   Matter lightbulb example - Binding target
+
+   Companion example to matter_switch_binding: a plain on/off Matter lightbulb
+   meant to be bound to a matter_switch_binding device so it can be toggled
+   directly by the switch, without a hub relaying every button press.
+
+   This device itself needs no special code for binding - a Matter Binding
+   only requires configuration on the initiating side (the switch's Binding
+   cluster + logic in MatterSwitch::beginWithBinding()). This lightbulb is a
+   plain OnOff server, identical to the matter_lightbulb example; it simply
+   accepts On/Off/Toggle commands from whichever node is authorized to send
+   them - which includes a bound switch once your Matter controller has:
+     1. Commissioned this device AND a matter_switch_binding device onto the
+        same Matter fabric.
+     2. Created the binding from the switch's endpoint to this device's
+        endpoint (see matter_switch_binding.ino for how).
+     3. Granted the switch's node the "Operate" ACL privilege on this
+        device's OnOff cluster - most controllers set this up automatically
+        as part of creating the binding.
+
+   The device has to be commissioned to a Matter hub first.
+
+   Compatible boards:
+   - Arduino Nano Matter
+   - SparkFun Thing Plus MGM240P
+   - xG24 Explorer Kit
+   - xG24 Dev Kit
+   - Seeed Studio XIAO MG24 (Sense)
+
+   Author: Silicon Labs
+ */
+#include <Matter.h>
+#include <MatterLightbulb.h>
+
+MatterLightbulb matter_bulb;
+
+void setup()
+{
+  Serial.begin(115200);
+  Matter.begin();
+  matter_bulb.begin();
+
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
+
+  Serial.println("Matter lightbulb - binding target");
+
+  if (!Matter.isDeviceCommissioned()) {
+    Serial.println("Matter device is not commissioned");
+    Serial.println("Commission it to your Matter hub with the manual pairing code or QR code");
+    Serial.printf("Manual pairing code: %s\n", Matter.getManualPairingCode().c_str());
+    Serial.printf("QR code URL: %s\n", Matter.getOnboardingQRCodeUrl().c_str());
+  }
+  while (!Matter.isDeviceCommissioned()) {
+    delay(200);
+  }
+
+  Serial.println("Waiting for Thread network...");
+  while (!Matter.isDeviceThreadConnected()) {
+    delay(200);
+  }
+  Serial.println("Connected to Thread network");
+
+  Serial.println("Waiting for Matter device discovery...");
+  while (!matter_bulb.is_online()) {
+    delay(200);
+  }
+  Serial.println("Matter device is now online");
+  Serial.println("Bind a matter_switch_binding device to this endpoint's OnOff cluster from your Matter controller");
+}
+
+void loop()
+{
+  static bool matter_lightbulb_last_state = false;
+  bool matter_lightbulb_current_state = matter_bulb.get_onoff();
+
+  // If the current state is ON and the previous was OFF - turn on the LED
+  if (matter_lightbulb_current_state && !matter_lightbulb_last_state) {
+    matter_lightbulb_last_state = matter_lightbulb_current_state;
+    digitalWrite(LED_BUILTIN, LED_BUILTIN_ACTIVE);
+    Serial.println("Bulb ON");
+  }
+
+  // If the current state is OFF and the previous was ON - turn off the LED
+  if (!matter_lightbulb_current_state && matter_lightbulb_last_state) {
+    matter_lightbulb_last_state = matter_lightbulb_current_state;
+    digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
+    Serial.println("Bulb OFF");
+  }
+}

libraries/Matter/examples/matter_switch_binding/matter_switch_binding.ino

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+/*
+   Matter switch with Binding cluster example
+
+   The example shows how to create a Matter momentary switch that uses the
+   standard Matter Binding cluster to control a bound light directly, without
+   a hub relaying every button press (see MatterSwitch::beginWithBinding()).
+
+   The device has to be commissioned to a Matter hub/controller first, same as
+   the plain matter_switch example. Once commissioned:
+     1. Commission this device AND a matter_lightbulb_binding device (the
+        companion example - a plain lightbulb, no special code needed on its
+        side) onto the same Matter fabric.
+     2. Create a binding from this switch's endpoint to the light's endpoint.
+        This isn't done from Home Assistant's own UI - use the underlying
+        Matter Server's dashboard (matterjs-server, the component behind HA's
+        Matter integration) to add the binding, or another controller with
+        binding support such as chip-tool.
+     3. Make sure the light grants this switch's node the "Operate" ACL
+        privilege on its OnOff cluster - most controllers set this up
+        automatically as part of creating the binding.
+
+   Once bound, pressing the on-board button toggles the bound light directly,
+   switch-to-light, without going through the controller for that command.
+
+   Compatible boards:
+   - Arduino Nano Matter
+   - SparkFun Thing Plus MGM240P
+   - xG24 Explorer Kit
+   - xG24 Dev Kit
+   - Seeed Studio XIAO MG24 (Sense)
+
+   Author: Silicon Labs
+ */
+#include <Matter.h>
+#include <MatterSwitch.h>
+
+MatterSwitch matter_switch;
+
+void handle_button_press();
+void handle_button_release();
+volatile bool button_pressed = false;
+
+void setup()
+{
+  Serial.begin(115200);
+  Matter.begin();
+  matter_switch.beginWithBinding();
+
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
+
+  // Set up the onboard button
+  #ifndef BTN_BUILTIN
+  #define BTN_BUILTIN PA0
+  #endif
+  pinMode(BTN_BUILTIN, INPUT_PULLUP);
+  attachInterrupt(BTN_BUILTIN, &handle_button_press, FALLING);
+  attachInterrupt(BTN_BUILTIN, &handle_button_release, RISING);
+
+  Serial.println("Matter switch with binding");
+
+  if (!Matter.isDeviceCommissioned()) {
+    Serial.println("Matter device is not commissioned");
+    Serial.println("Commission it to your Matter hub with the manual pairing code or QR code");
+    Serial.printf("Manual pairing code: %s\n", Matter.getManualPairingCode().c_str());
+    Serial.printf("QR code URL: %s\n", Matter.getOnboardingQRCodeUrl().c_str());
+  }
+  while (!Matter.isDeviceCommissioned()) {
+    delay(200);
+  }
+
+  Serial.println("Waiting for Thread network...");
+  while (!Matter.isDeviceThreadConnected()) {
+    delay(200);
+  }
+  Serial.println("Connected to Thread network");
+
+  Serial.println("Waiting for Matter device discovery...");
+  while (!matter_switch.is_online()) {
+    delay(200);
+  }
+  Serial.println("Matter device is now online");
+  Serial.println("Use your Matter controller to bind this switch to a light, then press the button to toggle it directly");
+}
+
+void loop()
+{
+  // If the physical button state changes - update the switch's state
+  static bool button_pressed_last = false;
+  if (button_pressed != button_pressed_last) {
+    button_pressed_last = button_pressed;
+    matter_switch.set_state(button_pressed);
+  }
+
+  // Get the current state of the Matter switch
+  static bool switch_last_state = false;
+  bool switch_current_state = matter_switch.get_state();
+
+  // If the current state is 'pressed' and the previous was 'not pressed' - switch pressed
+  if (switch_current_state && !switch_last_state) {
+    switch_last_state = switch_current_state;
+    digitalWrite(LED_BUILTIN, LED_BUILTIN_ACTIVE);
+    Serial.println("Switch pressed - toggling bound light(s)");
+  }
+
+  // If the current state is 'not pressed' and the previous was 'pressed' - switch released
+  if (!switch_current_state && switch_last_state) {
+    switch_last_state = switch_current_state;
+    digitalWrite(LED_BUILTIN, LED_BUILTIN_INACTIVE);
+    Serial.println("Switch released");
+  }
+}
+
+void handle_button_press()
+{
+  static uint32_t btn_last_press = 0;
+  if (millis() < btn_last_press + 200) {
+    return;
+  }
+  btn_last_press = millis();
+  button_pressed = true;
+}
+
+void handle_button_release()
+{
+  static uint32_t btn_last_press = 0;
+  if (millis() < btn_last_press + 200) {
+    return;
+  }
+  btn_last_press = millis();
+  button_pressed = false;
+}