build: the ES module build gets its own declarations

An ES module TypeScript consumer was given the CommonJS declarations in dist/types. With those,
`import alex2node from "alex2node"` compiled (module Node16) and then failed when Node loaded it: "The requested
module 'alex2node' does not provide an export named 'default'". The ES module build has named exports only.

tsconfig.esm.json now emits declarations next to dist/esm/*.js, under that directory's {"type": "module"}, and
"exports" selects per condition: import -> dist/esm/index.d.ts, require -> dist/types/index.d.ts. The default
import is now refused with TS1192; named imports are unchanged. "main", "module" and "types" are as before.

test/fixtures/types.mts holds the default import under @ts-expect-error, and a new test requires "types" before
"default" and a declaration for every built file. dist/: 25 files, 132,291 B -> 33 files, 155,647 B; the npm
tarball 25,125 B -> 25,837 B. npm test: 25 pass in 5.6 s.

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

dist/esm/AlexaStatusMessage.d.ts

@@ -0,0 +1,81 @@
+import type { MqttClient } from "mqtt";
+export declare enum EndpointHealth {
+    OK = "OK",
+    UNREACHABLE = "UNREACHABLE"
+}
+export declare enum ThermostatMode {
+    OFF = "OFF",
+    HEAT = "HEAT",
+    COOL = "COOL",
+    AUTO = "AUTO",
+    ECO = "ECO",
+    CUSTOM = "CUSTOM"
+}
+export declare enum PowerController {
+    ON = "ON",
+    OFF = "OFF"
+}
+export declare enum TemperatureSensorScale {
+    CELSIUS = "CELSIUS",
+    FAHRENHEIT = "FAHRENHEIT"
+}
+interface ContextProperty {
+    namespace: string;
+    name: string;
+    value: any;
+    timeOfSample: string;
+    uncertaintyInMilliseconds: number;
+    instance?: string;
+}
+/** Why a ChangeReport is sent (Alexa.ChangeReport payload.change.cause.type). */
+export type ChangeCause = "APP_INTERACTION" | "PHYSICAL_INTERACTION" | "PERIODIC_POLL" | "RULE_TRIGGER" | "VOICE_INTERACTION";
+export declare class AlexaStatusMessage {
+    private context;
+    /** ChangeReport only: the properties that changed (payload.change.properties); the rest go to context. */
+    private changeProps;
+    private changeCause;
+    private target;
+    private event;
+    private rootTopic;
+    private endpointId;
+    private mqttClient;
+    private isDeferred;
+    /** 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, isResponse?: boolean, isDeferred?: boolean, changeCause?: ChangeCause | null);
+    private getTimestamp;
+    private addProperty;
+    /** ChangeReport: the add*Prop calls that follow describe what CHANGED (the default for a change report). */
+    changed(): this;
+    /** ChangeReport: the add*Prop calls that follow describe the other, unchanged properties (context). */
+    unchanged(): this;
+    /** True for a ChangeReport (Device.getChangeReport). */
+    isChangeReport(): boolean;
+    /** The message as it will be published (for tests and logging). */
+    toJSON(): {
+        event: any;
+        context: {
+            properties: ContextProperty[];
+        } | null;
+    };
+    addModeControllerProp(instance: string, value: string, uncertaintyInMs?: number): this;
+    addThermostatModeProp(mode: string, uncertaintyInMs?: number): this;
+    addEstimatedDeferralTime(seconds: number): this;
+    addThermostatControllerProp(name: "lowerSetpoint" | "upperSetpoint" | "targetSetpoint", scale: TemperatureSensorScale, value: number, uncertaintyInMs?: number): this;
+    /** Alexa.EndpointHealth connectivity: EndpointHealth.OK / UNREACHABLE (the plain strings "OK" / "UNREACHABLE" are accepted too). */
+    addHealthProp(health: EndpointHealth | `${EndpointHealth}`, uncertaintyInMs?: number): this;
+    addPowerControllerProp(power: PowerController, uncertaintyInMs?: number): this;
+    addTemperatureSensorProp(scale: TemperatureSensorScale, value: number, uncertaintyInMs?: number): this;
+    addBrightnessControllerProp(brightness: number, uncertaintyInMs?: number): this;
+    addColorTemperatureControllerProp(colorTemp: number, uncertaintyInMs?: number): this;
+    addToggleControllerProp(state: PowerController, instance: string, uncertaintyInMs?: number): this;
+    addContextProp(prop: ContextProperty): this;
+    /**
+     * Publish: a Response/StateReport to <root>/<endpoint>/alexaResponce (sendAsync: deferredResponse), a ChangeReport
+     * to <root>/changeReport (Alex2MQTT adds the user's token and posts it to the Alexa event gateway). Resolves with
+     * the topic, or "" when the publish failed - the error then goes to the bridge's "error" event (when listened to).
+     * Never rejects (1.5.1 did, so an un-caught send() could kill the host).
+     */
+    send(sendAsync?: boolean): Promise<string>;
+}
+export {};