registry: SceneController events, DoorbellEventSource, SimpleEventSource, TimeHoldController, InventoryLevelSensor, WakeOnLANController

Six descriptors written from their pages replace the last stubs of tiers 1 and 2. A scene answers Activate and
Deactivate through ctx.respond() with ActivationStarted and DeactivationStarted, the time and the cause filled
in. device.raise(descriptor, name, payload) publishes DoorbellPress and the Event of a button on <root>/event
with the endpoint and a new messageId; it throws a MessageError for an interface or instance the device did
not declare, an event that answers a directive, a payload that does not fit and a message over 16000 bytes.
TurnOn of a device with WakeOnLANController is deferred without the warning.

On the wire: a doorbell has no properties object and proactivelyReported on the capability; SimpleEventSource
is version 1.0, InventoryLevelSensor and WakeOnLANController version 3 (1.5.2: 1). A scene declared without
options is announced as before. Alex2MQTT has no topic yet for the WakeUp event.
24 examples of the six pages are saved as fixtures. 267 tests pass, 241 before.

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

test/fixtures/alexa-docs/alexa-inventorylevelsensor/ChangeReport.json

@@ -0,0 +1,65 @@
+{
+  "event": {
+    "header": {
+      "namespace": "Alexa",
+      "name": "ChangeReport",
+      "messageId": "Unique identifier, preferably a version 4 UUID",
+      "payloadVersion": "3"
+    },
+    "endpoint": {
+      "scope": {
+        "type": "BearerToken",
+        "token": "OAuth2.0 bearer token"
+      },
+      "endpointId": "Endpoint ID"
+    },
+    "payload": {
+      "change": {
+        "cause": {
+          "type": "PERIODIC_POLL"
+        },
+        "properties": [
+          {
+            "namespace": "Alexa.InventoryLevelSensor",
+            "instance": "InkSensor.Cyan",
+            "name": "level",
+            "value": {
+              "@type": "Volume",
+              "value": 5,
+              "unit": "MILLILITER"
+            },
+            "timeOfSample": "2019-10-31T17:00:00.00Z",
+            "uncertaintyInMilliseconds": 0
+          },
+          {
+            "namespace": "Alexa.InventoryLevelSensor",
+            "instance": "PaperSensor.FrontTray",
+            "name": "level",
+            "value": {
+              "@type": "Count",
+              "value": 200
+            },
+            "timeOfSample": "2019-10-31T17:00:00.00Z",
+            "uncertaintyInMilliseconds": 0
+          },
+          {
+            "namespace": "Alexa.PowerController",
+            "name": "powerState",
+            "value": "ON",
+            "timeOfSample": "2019-10-31T17:00:00.00Z",
+            "uncertaintyInMilliseconds": 0
+          }
+        ]
+      }
+    }
+  },
+  "context": {
+    "namespace": "Alexa.EndpointHealth",
+    "name": "connectivity",
+    "value": {
+      "value": "OK"
+    },
+    "timeOfSample": "2019-10-31T16:58:10:00.00Z",
+    "uncertaintyInMilliseconds": 0
+  }
+}