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/EndpointHealth.js

@@ -0,0 +1,29 @@
+import { s } from "../schema.js";
+import { defineInterface } from "../types.js";
+export const CONNECTIVITY_REASONS = [
+    "WIFI_BAD_PASSWORD", "WIFI_AP_NOT_FOUND", "WIFI_ROUTER_UNREACHABLE", "WIFI_AP_CHANNEL_QUALITY_LOW",
+    "INTERNET_UNREACHABLE", "CAPTIVE_PORTAL_CHECK_FAILED", "UNKNOWN",
+];
+/**
+ * Version 3.1, as the page is titled. It defines connectivity only. Examples on other pages declare 3 and 3.2;
+ * alex2node 1.x declared 3.3, which no page mentions.
+ */
+export const EndpointHealth = defineInterface({
+    namespace: "Alexa.EndpointHealth",
+    version: "3.1",
+    doc: "https://developer.amazon.com/docs/alexaplus/device-apis/alexa-endpointhealth.html",
+    kind: "sensor",
+    tier: 1,
+    instanced: false,
+    properties: {
+        connectivity: {
+            name: "connectivity",
+            value: s.object({
+                value: s.enum("OK", "UNREACHABLE"),
+                reason: s.optional(s.enum(...CONNECTIVITY_REASONS)),
+            }),
+            note: "in every Response, StateReport and ChangeReport; a change of it reported within three seconds",
+        },
+    },
+    directives: {},
+});