messages: pure builders for every event the bridge sends

src/messages builds Response, StateReport, DeferredResponse, ErrorResponse, ChangeReport and the scene, doorbell
and simple events from plain values; messageId and times are parameters, so a test compares whole objects.
StateBuilder collects properties checked by the descriptors, AlexaError and AlexaErrors carry the payload fields
of an error type. AlexaStatusMessage and AlexaErrorResponse move to src/compat and are written on the builders.
On the wire, against 1.5.2: a DeferredResponse has no context key, a ChangeReport has no correlationToken, the
namespace of an ErrorResponse follows its type, and a ChangeReport without a changed property is not published:
send() resolves "" and the bridge reports an error that names the endpoint.
143 tests pass (108 before).

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

dist/esm/compat/AlexaErrorResponse.d.ts

@@ -0,0 +1,26 @@
+import type { MqttClient } from "mqtt";
+import type { ErrorResponseMessage } from "../messages/types.js";
+/** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
+export declare class AlexaErrorResponse {
+    private readonly correlationToken;
+    private readonly rootTopic;
+    private readonly endpointId;
+    private readonly mqttClient;
+    private error;
+    private namespace?;
+    private readonly messageId;
+    /** Where a failed publish is reported (set by the Device that built this message, 1.5.2): send() never rejects. */
+    onPublishError?: (err: Error) => void;
+    constructor(correlationToken: string, rootTopic: string, endpointId: string, mqttClient: MqttClient);
+    /**
+     * The error to answer with. otherParams are the fields the type adds to the payload (validRange). The header
+     * carries the namespace the type is documented under, Alexa.ThermostatController for THERMOSTAT_IS_OFF;
+     * options.namespace names another.
+     */
+    setErrorMessage(type: string, message: string, otherParams?: Record<string, any>, options?: {
+        namespace?: string;
+    }): void;
+    toJSON(): ErrorResponseMessage;
+    /** Resolves with the topic published to, or "" when the publish failed. Never rejects. */
+    send(sendAsync?: boolean): Promise<string>;
+}