registry: describe an Alexa interface as data

src/registry/ holds what the library knows about an interface: namespace, version, the page it was read from,
properties with their value schemas and directives with their payload schemas. Five interfaces are described
(Alexa, PowerController, BrightnessController, TemperatureSensor, EndpointHealth); the other 65 names of
AlexaInterfaceType are stubs with the version and property names of 1.5.2. schema.ts is the run-time check behind
it (241 lines, no new dependency), catalog.ts the vocabularies of the pages: 103 assets (23 units), 6 actions,
9 states, 56 display categories, 22 reserved words, 73 error types under 11 namespaces.

AlexaInterface.getVersion() and getProps() read the registry; the two switch statements are gone (-167 lines).
On the wire: Alexa.EndpointHealth is announced at 3.1 (was 3.3; the page is titled 3.1 and no page mentions 3.3),
and TimeHoldController and Camera.LiveViewController at 3 and 1.7 (1.5.2 sent the string "UNKNOWN").
DisplayCategory gains VACUUM. New exports: registry, DeclarationError, SchemaError, Assets, Units, Actions,
States, DisplayCategories and the descriptor types.

Tests: 20 JSON examples of the five pages under test/fixtures/alexa-docs; every directive payload and property
value in them parses with its descriptor. npm test: 57 pass (was 30) in 10.8 s, also on Node 18.20.8 and 20.20.2.

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

dist/esm/registry/interfaces/Alexa.js

@@ -0,0 +1,20 @@
+import { s } from "../schema.js";
+import { defineInterface } from "../types.js";
+/**
+ * The base interface: every endpoint lists it (alexa-interface.html, "Support the Alexa interface in all add-ons").
+ * Its one directive to a device is ReportState, answered with a StateReport.
+ */
+export const Alexa = defineInterface({
+    namespace: "Alexa",
+    version: "3",
+    doc: "https://developer.amazon.com/docs/alexaplus/device-apis/alexa-interface.html",
+    kind: "base",
+    tier: 1,
+    instanced: false,
+    properties: {},
+    directives: {
+        ReportState: { name: "ReportState", payload: s.object({}) },
+    },
+    // { type, interface, version } and nothing else, as in the discovery example of the page
+    discovery: () => ({ properties: false }),
+});