discovery: generate capability JSON from the registry

A capability is a descriptor plus what the endpoint declares (device/Capability.ts), and its discovery object is
generated from the two. The new API is bridge.addDevice({ endpointId, name, categories, ... }) and
device.add(PowerController, options): both throw a DeclarationError that names the endpoint, the interface and
the instance (device/validate.ts), and leave the bridge and the device as they were. AlexaInterface is the same
Capability with the 1.x methods on it; it, ActionMapping and the enums moved to src/compat/, Device to src/device/.

What a 1.x caller can observe:
- every endpoint ends with { type: "AlexaInterface", interface: "Alexa", version: "3" } (alexa-interface.html);
  new Alex2MQTT(..., { alexaInterface: false }) leaves it out
- the fields of a capability object come in the order of Amazon's examples; their content is unchanged
- addCapability() with a name that is not an interface throws (1.5.2 announced it with the version "UNKNOWN")
- ActionMapping takes the payload as an object; a JSON string is parsed (1.5.2 sent the string), any other throws
- what Alexa would reject in a 1.x declaration is not refused: device.check() lists it and the bridge logs each
  line once, as "warning: ..." through the log hook, when it answers a discovery
- a device whose JSON cannot be built is left out of the answer and reported as an error event
- PowerController and EndpointHealth are the descriptors and keep ON/OFF and OK/UNREACHABLE; PowerState is new

Tests: six zoo devices declared the 1.x way give the JSON that Alexa accepted from 1.5.2 on 2026-09-28, plus the
Alexa capability. npm test: 85 pass (was 57) in 10-12 s, also on Node 18.20.8 and 20.20.2.

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

dist/esm/Alex2Node.d.ts

@@ -1,7 +1,8 @@
 import type { IClientOptions } from "mqtt";
-import Device from "./Device.js";
+import Device from "./device/Device.js";
+import type { EndpointDefinition } from "./device/Device.js";
 import { EventEmitter } from "events";
-import { DisplayCategory } from "./DisplayCategory.js";
+import { DisplayCategory } from "./compat/enums.js";
 /** Optional settings for the bridge (1.5.1). Everything has the 1.4.0 behaviour as its default. */
 export interface Alex2MQTTOptions {
     /** The broker URL. Default: the public Alex2MQTT broker, mqtt://Alex2MQTT.stormysdream.club:1883. */
@@ -10,6 +11,11 @@ export interface Alex2MQTTOptions {
     mqtt?: IClientOptions;
     /** Where log lines go. Default: console (only when debugLogging is on). */
     log?: (message: string, detail?: unknown) => void;
+    /**
+     * false: discovery does not list the Alexa interface on the endpoints. Default: every endpoint ends with
+     * { type: "AlexaInterface", interface: "Alexa", version: "3" }, which Amazon requires and 1.x left out.
+     */
+    alexaInterface?: boolean;
 }
 export declare const DEFAULT_HOST = "mqtt://Alex2MQTT.stormysdream.club:1883";
 /**
@@ -35,6 +41,7 @@ declare class Alex2MQTT extends EventEmitter {
     private devices;
     private MqttHost;
     private options;
+    private logged;
     /** true while the broker connection is up. */
     connected: boolean;
     /** ISO time of the last discovery request answered, null before the first. */
@@ -44,9 +51,22 @@ declare class Alex2MQTT extends EventEmitter {
     /** Emit "error" only when somebody listens: an unhandled "error" event would crash the host process. */
     private fail;
     connect(): void;
+    private describeDevices;
     /** Close the broker connection (resolves once closed). The devices stay registered; connect() again reuses them. */
     disconnect(): Promise<void>;
-    registerDevice(name: string, endpointId: string, displayCategory: DisplayCategory | DisplayCategory[] | null): Device;
+    /**
+     * Declare a device:
+     *
+     *   const blinds = bridge.addDevice({ endpointId: "bedroom-blinds", name: "Bedroom Blinds",
+     *     categories: ["INTERIOR_BLIND"], manufacturerName: "Acme", description: "Roller blind by Acme" });
+     *
+     * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
+     * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
+     * unless endpointHealth is false.
+     */
+    addDevice(definition: EndpointDefinition): Device;
+    registerDevice(name: string, endpointId: string, displayCategory?: DisplayCategory | DisplayCategory[] | null): Device;
+    private register;
     /** Forget a device (its listeners with it). Returns false when there was none. */
     unregisterDevice(endpointId: string): boolean;
     /** Forget every device. */