feat(scripted-alarms): materialise real Part 9 AlarmConditionState nodes (T14)

docs/v2/f14b-part9-sdk-notes.md

@@ -581,11 +581,20 @@ ServiceResult OnAck(ISystemContext ctx, ConditionState c, byte[] eventId, Locali
    confirm `Server.Telemetry` (`ITelemetryContext`) is non-null in our host
    before relying on the telemetry ctor — fall back to `new AlarmConditionState(parent)`
    if not. (Not load-bearing; pick whichever the host supports.)
-2. **Optional children before `Create`.** Whether `ShelvingState` /
-   `ConfirmedState` are auto-created by `Create` or must be instantiated first
-   (the sample instantiates them) — **[SAMPLE-ONLY]** behaviour; verify by
-   inspecting the live node after `Create` (browse the children). If Confirm /
-   Shelve children are missing, materialise them like the sample before `Create`.
+2. **Optional children before `Create`.** ~~Whether `ShelvingState` /
+   `ConfirmedState` are auto-created by `Create` or must be instantiated first.~~
+   **RESOLVED in T14 (real-server integration test, 1.5.378.106):** `Create`
+   auto-builds the **full** optional Part 9 child set from the embedded type
+   definition with **no** pre-setting — for `OffNormalAlarmState`, both
+   `ConfirmedState` AND `ShelvingState` come back **non-null** after `Create`
+   (richer than the `[SAMPLE-ONLY]` caveat predicted). So T15/T16 can call
+   `SetConfirmedState` / `SetShelvingState` directly; no manual child
+   materialisation is needed. **Gotcha also found:** `BranchId.Value` is left a
+   **null reference** by `Create`, and the very first `Set*` call
+   (`SetEnableState` → `UpdateRetainState` → `GetRetainState` → `IsBranch()`)
+   **NREs** on it. Fix: set `alarm.BranchId.Value = NodeId.Null` (the main
+   branch) **before** any `Set*` call. T14's `MaterialiseAlarmCondition` does
+   this. (Covered by `SdkAddressSpaceSinkTests.MaterialiseAlarmCondition_*`.)
 3. **`InstanceStateSnapshot` vs reporting the node directly.** The sample uses
    an `InstanceStateSnapshot` as the `IFilterTarget`. Confirm whether reporting
    the alarm node itself (which is also an `IFilterTarget`) is acceptable — the