registry: Speaker, StepSpeaker, EqualizerController, PlaybackController, PlaybackStateReporter, InputController, ChannelController

Seven descriptors written from their pages replace seven stubs. All are version 3; 1.5.2 announced Speaker,
StepSpeaker, EqualizerController and PlaybackStateReporter as version 1, and all but ChannelController without
a property. StepSpeaker has no properties object in discovery and PlaybackController one without fields, next
to supportedOperations; a directive for an operation the device did not list is answered with
INVALID_DIRECTIVE. The equalizer declares bands, modes or both under "configurations", a TV its inputs from
the 61 names of the page.

Not described: the lineup of ChannelController, whose discovery example the page folds away. The discovery
examples of InputController spell one key "friendNames"; the fixtures have friendlyNames, as its table does.
62 examples of the six pages are saved as fixtures. 241 tests pass, 215 before.

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

dist/esm/registry/interfaces/PlaybackController.js

@@ -0,0 +1,43 @@
+import { s } from "../schema.js";
+import { defineInterface } from "../types.js";
+// In the order of the discovery example
+const OPERATIONS = ["Play", "Pause", "Stop", "Next", "Previous", "FastForward", "Rewind", "StartOver"];
+// Alexa sends the operations the capability lists
+const operation = (name) => ({
+    name,
+    payload: s.object({}),
+    when: ({ options }) => (options.supportedOperations ?? OPERATIONS).includes(name),
+});
+/**
+ * Play, pause and the other buttons of a player. The interface reports nothing: what plays is the playbackState of
+ * Alexa.PlaybackStateReporter, which a Response to these directives has in its context. Errors of a video device go
+ * under Alexa.Video, the others under Alexa.
+ */
+export const PlaybackController = defineInterface({
+    namespace: "Alexa.PlaybackController",
+    version: "3",
+    doc: "https://developer.amazon.com/docs/alexaplus/device-apis/alexa-playbackcontroller.html",
+    kind: "controller",
+    tier: 2,
+    instanced: false,
+    properties: {},
+    directives: {
+        Play: operation("Play"),
+        Pause: operation("Pause"),
+        Stop: operation("Stop"),
+        Next: operation("Next"),
+        Previous: operation("Previous"),
+        FastForward: operation("FastForward"),
+        Rewind: operation("Rewind"),
+        StartOver: operation("StartOver"),
+    },
+    options: s.object({
+        /** Default: all eight. */
+        supportedOperations: s.optional(s.array(s.enum(...OPERATIONS), { min: 1 })),
+    }, { unknownKeys: "reject" }),
+    // The example has a properties object without fields, which topLevel puts where properties: false left none
+    discovery: ({ options: { supportedOperations = [...OPERATIONS] } }) => ({
+        properties: false,
+        topLevel: { properties: {}, supportedOperations },
+    }),
+});