examples: one runnable file per recipe on the 2.0 API, the 1.x files in examples/legacy

Ten recipes: lamp, colour lamp, thermostat, blind, lock (deferred), contact
sensor (ChangeReport), scene, doorbell (raise), typed errors, and a plug as an
ES module. Each reads ALEX2MQTT_USERNAME, _PASSWORD and _ROOT_TOPIC and names
the ones that are missing. The nine examples of 1.5.2 move to examples/legacy
unchanged.

test/examples.test.js starts every file with node, its broker connection sent
to a broker on 127.0.0.1 (test/helpers/loopback.js), discovers the device,
sends directives and checks the answers. A legacy file is started and its
discovery compared with the answer the 1.5.2 build gave, recorded in
test/fixtures/legacy-examples.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

examples/legacy/ExamplePowerControllerWithMomentary.js

@@ -0,0 +1,111 @@
+// Import the library ("alex2node" is the installed package; inside this checkout it resolves to the built dist/ via package.json "exports")
+const {
+  Alex2MQTT,
+  AlexaInterfaceType,
+  PowerController,
+  DisplayCategory,
+  EndpointHealth
+} = require("alex2node");
+
+require("dotenv").config(); // Load environment variables from .env file
+
+// Simulated in-memory device state
+let outputState = PowerController.OFF;
+const momentaryModeInstance = "mode.signal.beep";
+const defaultMomentaryMode = "mode.signal.beep.Normal";
+
+// Load MQTT connection credentials and root topic from environment variables
+const username = process.env.MQTT_USERNAME;
+const password = process.env.MQTT_PASSWORD;
+const rootTopic = process.env.MQTT_ROOT_TOPIC;
+
+// Create and initialize a new Alexa-to-MQTT client
+const alex2NodeClient = new Alex2MQTT(username, password, rootTopic, false);
+alex2NodeClient.connect(); // Connect to the MQTT broker
+alex2NodeClient.on("error", (e) => console.error("broker:", e.message)); // Log broker errors (on 1.5.0 this listener is also what keeps an outage from killing the process)
+
+// Define the device name and register it
+const deviceName = "Kitchen Light";
+const kitchenLight = alex2NodeClient.registerDevice(
+  deviceName,
+  "kitchen-light-1",
+  [DisplayCategory.LIGHT]
+);
+
+// Add PowerController capability
+kitchenLight.addCapability(AlexaInterfaceType.POWER_CONTROLLER);
+
+// Add ModeController for momentary "beep" functionality
+const momentaryController = kitchenLight.addCapability(AlexaInterfaceType.MODE_CONTROLLER);
+momentaryController.setInstance(momentaryModeInstance);
+momentaryController.addFriendlyName("Signal", "en-US");
+momentaryController.addSupportedModes([
+  {
+    value: "mode.signal.beep.Normal",
+    modeResources: {
+      friendlyNames: [{
+        "@type": "text",
+        value: { text: "Normal", locale: "en-US" }
+      }]
+    }
+  },
+  {
+    value: "mode.signal.beep.Beep",
+    modeResources: {
+      friendlyNames: [{
+        "@type": "text",
+        value: { text: "Beep", locale: "en-US" }
+      }]
+    }
+  }
+]);
+
+// Log the device name to verify registration
+console.log(kitchenLight.getName());
+
+/**
+ * Handle Alexa's ReportState directive
+ */
+kitchenLight.on("ReportState", (payload) => {
+  console.log("ReportState received!", payload);
+  const { correlationToken } = payload.header;
+  const status = kitchenLight.getStatusMessage(correlationToken);
+  status
+    .addHealthProp(EndpointHealth.OK)
+    .addPowerControllerProp(outputState)
+    .addModeControllerProp(momentaryModeInstance, defaultMomentaryMode);
+  status.send();
+});
+
+/**
+ * Handle incoming directives (PowerController and ModeController)
+ */
+kitchenLight.on("Event", (directive, interfaceType) => {
+  console.log("Event received", { directive, interfaceType });
+  const { name, correlationToken, instance } = directive.header;
+
+  const status = kitchenLight.getStatusMessage(correlationToken, true).addHealthProp(EndpointHealth.OK);
+
+  // PowerController logic
+  if (interfaceType === AlexaInterfaceType.POWER_CONTROLLER) {
+    if (name === "TurnOn") {
+      outputState = PowerController.ON;
+      console.log("Turning ON the Kitchen Light");
+    } else if (name === "TurnOff") {
+      outputState = PowerController.OFF;
+      console.log("Turning OFF the Kitchen Light");
+    }
+    status.addPowerControllerProp(outputState);
+  }
+
+  // Momentary ModeController logic
+  else if (interfaceType === AlexaInterfaceType.MODE_CONTROLLER && instance === momentaryModeInstance) {
+    if (name === "SetMode") {
+      const modeValue = directive.payload.mode;
+      console.log(`[Momentary Trigger] Received mode: ${modeValue}`);
+    }
+    status.addModeControllerProp(momentaryModeInstance, defaultMomentaryMode);
+  }
+
+  status.send();
+});