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/types/registry/index.d.ts

@@ -14,7 +14,7 @@ export declare const registry: {
 };
 export { Alexa, BrightnessController, EndpointHealth, PowerController, TemperatureSensor };
 export { DeclarationError, defineInterface } from "./types.js";
-export type { AnyDescriptor, CapabilityExtras, Declared, DirectiveDescriptor, EndpointView, EventDescriptor, InterfaceDescriptor, Label, PropertyDescriptor, } from "./types.js";
+export type { ActionsToDirective, AnyDescriptor, CapabilityExtras, Declared, DirectiveDescriptor, EndpointView, EventDescriptor, InterfaceDescriptor, Label, PropertyDescriptor, Semantics, StatesToRange, StatesToValue, } from "./types.js";
 export { s, SchemaError } from "./schema.js";
 export type { Infer, Schema, Temperature, TimeInterval } from "./schema.js";
 export * from "./catalog.js";

dist/types/registry/resources.d.ts

@@ -0,0 +1,13 @@
+import type { AssetId } from "./catalog.js";
+import type { Schema } from "./schema.js";
+import type { Label } from "./types.js";
+/** A friendly name as text, in one locale. */
+export declare function text(name: string, locale?: string): Label;
+/** A friendly name from the global Alexa catalog: one id, several names, every language Alexa speaks. */
+export declare function asset(assetId: AssetId): Label;
+/** One friendly name. An asset has to be in the catalog, a text must not be a word Alexa keeps for itself. */
+export declare const label: Schema<Label>;
+/** The friendly names of an instance, a mode or a preset: at least one. */
+export declare const labels: Schema<Label[]>;
+/** What the user is shown for a friendly name: the text, or the id of the asset. */
+export declare function shownAs(name: Label): string;

dist/types/registry/schema.d.ts

@@ -44,6 +44,10 @@ export interface TimeInterval {
     end?: string;
     duration?: string;
 }
+/** The error of a value that is not what a schema expects. */
+export declare function mismatch(path: string, expects: string, input: unknown): SchemaError;
+/** The path of a key of the object at path. */
+export declare const at: (path: string, key: string) => string;
 declare function number(rules?: NumberRules): Schema<number>;
 declare function string(rules?: {
     min?: number;
@@ -54,6 +58,8 @@ declare function string(rules?: {
 declare function boolean(): Schema<boolean>;
 declare function literal<V extends string | number | boolean | null>(value: V): Schema<V>;
 declare function enumeration<V extends readonly string[]>(...values: V): EnumSchema<V[number]>;
+/** One of a list too long to print in an error message: expects says what the list is. */
+declare function oneOf<V extends string>(values: readonly V[], expects: string): EnumSchema<V>;
 declare function unknown(): Schema<unknown>;
 declare function optional<T>(inner: Schema<T>): OptionalSchema<T>;
 declare function nullable<T>(inner: Schema<T>): Schema<T | null>;
@@ -78,6 +84,7 @@ export declare const s: {
     boolean: typeof boolean;
     literal: typeof literal;
     enum: typeof enumeration;
+    oneOf: typeof oneOf;
     unknown: typeof unknown;
     optional: typeof optional;
     nullable: typeof nullable;

dist/types/registry/types.d.ts

@@ -15,6 +15,35 @@ export type Label = {
         assetId: string;
     };
 };
+/** Phrases ("open", "lower") mapped to one directive (alexa-discovery-objects.html, "ActionMappings object"). */
+export interface ActionsToDirective {
+    "@type": "ActionsToDirective";
+    actions: string[];
+    directive: {
+        name: string;
+        payload?: Record<string, unknown>;
+    };
+}
+/** States ("open", "closed") mapped to a value of the property (same page, "StateMappings object"). */
+export interface StatesToValue {
+    "@type": "StatesToValue";
+    states: string[];
+    value: unknown;
+}
+/** States mapped to a range of values of the property. */
+export interface StatesToRange {
+    "@type": "StatesToRange";
+    states: string[];
+    range: {
+        minimumValue: number;
+        maximumValue: number;
+    };
+}
+/** The semantics object of a generic controller: at least one of the two lists. */
+export interface Semantics {
+    actionMappings?: ActionsToDirective[];
+    stateMappings?: Array<StatesToValue | StatesToRange>;
+}
 export interface PropertyDescriptor<V> {
     name: string;
     value: Schema<V>;
@@ -49,7 +78,7 @@ export interface CapabilityExtras {
     properties?: false;
 }
 /** A capability as declared on an endpoint: what discovery() and validate() of its descriptor are given. */
-export interface Declared<O = Record<string, unknown>> {
+export interface Declared<O = unknown> {
     readonly endpointId: string;
     readonly namespace: string;
     /** "" when the interface is declared without an instance. */
@@ -67,7 +96,7 @@ export interface EndpointView {
     readonly friendlyName: string;
     readonly description: string;
     readonly displayCategories: readonly string[];
-    /** The other capabilities of the endpoint. */
+    /** The capabilities declared on the endpoint before this one. */
     readonly capabilities: readonly Declared[];
 }
 export type Properties = Record<string, PropertyDescriptor<any>>;