fix(alarms): native ack refused off-Primary, commented re-ack reported, real UnshelveTime (#597)

- Native-condition Acknowledge on a non-Primary node returns BadInvalidState (nothing
  routed/applied/reported) via NativeAlarmAckPrimaryGate, fed from
  IDriverPrimaryRoleSource by OtOpcUaServerHostedService.
- A re-ack carrying a comment reports one comment event (Acked/Confirmed unchanged).
- TimedShelve applies its requested duration and the scripted projection carries
  UnshelveAtUtc, so ShelvingState/UnshelveTime counts down instead of ~24.8 days.
- Native re-ack still routed to the driver (deliberate: documented retry path), pinned.
- AdminUI /alerts client ack/shelve path test; docs/AlarmTracking.md decisions incl.
  accepted SDK EventsMonitored residual (item 6).
- Also #599/03/S20: RemoveEquipmentSubtree severs inverse Organizes edges.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

docs/AlarmTracking.md

@@ -292,8 +292,9 @@ branches on native-ness and routes through a dedicated path — separate
 from the scripted `AlarmCommandRouter`:
 
 1. **`OtOpcUaNodeManager.HandleNativeAlarmAck`** — gates on the caller's
-   `AlarmAck` role (fails closed: no role → `BadUserAccessDenied`), then
-   dispatches a `NativeAlarmAck(ConditionNodeId, Comment, OperatorUser)`
+   `AlarmAck` role (fails closed: no role → `BadUserAccessDenied`), then on the
+   node's redundancy role (not the Primary → `BadInvalidState`, see
+   §"Acknowledge on a non-Primary node" below), then dispatches a `NativeAlarmAck(ConditionNodeId, Comment, OperatorUser)`
    to the `NativeAlarmAckRouter` seam (fire-and-forget, non-blocking under
    the node-manager Lock). `OperatorUser` carries the authenticated
    session principal's display name.
@@ -331,20 +332,38 @@ projection's Retain rule, `Active || !Acked`) after the SDK handler, before the
 one ack event. ScadaBridge maps `ConfirmedState` into its alarm state, so this
 is client-visible.
 
-> **Secondary-node ack flap.** On a node that is not the redundancy Primary,
-> an OPC UA Acknowledge is applied to the local condition and reported (one
-> event, Acked), but `DriverHostActor`'s Primary gate drops the route upstream.
-> The driver never acknowledges, so its next transition for that alarm is
-> projected with `Acked = false` and the node reverts — with its own event. A
-> client acking against the Secondary sees acked → unacked. Ack against the
-> Primary (the higher ServiceLevel) for the ack to stick.
+> **Acknowledge on a non-Primary node is refused** (Gitea #597). On a node
+> that is not the redundancy Primary, an OPC UA Acknowledge of a **native**
+> condition returns **`BadInvalidState`** ("not the redundancy Primary;
+> acknowledge on the Primary") — nothing is routed, applied or reported. The
+> verdict is the same data-plane one the device-write gate and
+> `DriverHostActor`'s ack route use (`PrimaryGatePolicy.ShouldServiceAsPrimary`,
+> published to `IDriverPrimaryRoleSource` on every redundancy snapshot and
+> wired onto the node manager by `OtOpcUaServerHostedService`). It is checked
+> after authorization, so a caller who may not ack learns nothing about the
+> node's role.
+>
+> This replaces a documented flap: the Secondary used to apply and report the
+> ack locally while `DriverHostActor` dropped the route upstream, so the driver
+> never acknowledged, its next transition projected `Acked = false`, and the
+> client saw acked → unacked. An honest refusal is client-visible — a client
+> (ScadaBridge included) that acks against the Secondary now gets a Bad result
+> instead of a Good that later reverts — so ack against the Primary (the higher
+> ServiceLevel). Scripted conditions are **not** gated: their engine runs on
+> both nodes, so an ack on the Secondary is real. Residual: the published
+> verdict changes only on a redundancy snapshot, so in the boot window of a
+> multi-node cluster (no snapshot yet) the node still accepts, while
+> `DriverHostActor`'s live check may drop the route — the old flap, limited to
+> that window.
 
 > **Best-effort during reconnect.** If a native ack arrives while the owning
-> driver is `Connecting`/`Reconnecting` (or on a non-Primary node), it is
-> dropped with a debug log and **not** retried upstream — the OPC UA Part 9
-> `AlarmConditionState` was already committed locally at step 1, so the rare
-> outcome is "acked locally but not propagated to AVEVA." Re-issue the ack once
-> the driver is reconnected if upstream propagation is required.
+> driver is `Connecting`/`Reconnecting` (or, in the boot window above, on a
+> node whose role is not yet known), it is dropped with a debug log and **not**
+> retried upstream — the OPC UA Part 9 `AlarmConditionState` was already
+> committed locally at step 1, so the rare outcome is "acked locally but not
+> propagated to AVEVA." Re-issue the ack once the driver is reconnected if
+> upstream propagation is required — a re-ack of a node already showing Acked
+> is still routed to the driver for exactly this reason.
 
 ### Legacy sub-attribute path
 
@@ -412,8 +431,9 @@ reports nothing.
   `AreEventsMonitored` bookkeeping, which is imprecise for conditions
   materialised under an already-subscribed folder.
 - **The SDK's shelve methods never apply shelving state** (they only call
-  `OnShelve`), so the wrapper applies it — with the same
-  `(shelved, oneShot, 0)` mapping the projection uses — before reporting.
+  `OnShelve`), so the wrapper applies it — with the same `(shelved, oneShot)`
+  mapping the projection uses, and a TimedShelve with its requested duration —
+  before reporting.
 - **The re-projection does not duplicate it.** The engine's (or driver's)
   answer to the routed command reaches `WriteAlarmCondition`'s delta-gate,
   which compares against the node's current state — already the new state —
@@ -425,7 +445,16 @@ reports nothing.
   nothing. The SDK accepts acknowledging an acknowledged condition and sets
   `Confirmed = false` again, so a re-ack also restores the pre-call Confirmed
   and Retain — silent, and a scripted node never drifts from its engine.
-  AddComment always reports (the comment is the change).
+  AddComment always reports (the comment is the change), and so does a re-ack
+  **carrying a comment** (Gitea #597): the SDK writes that comment to the node,
+  so it is reported once, with Acked/Confirmed unchanged. Before #597 the
+  comment landed on the node but no subscriber ever saw it.
+- **A native re-ack is still routed to the driver** (deliberate, #597). The
+  route is fire-and-forget, so a node showing Acked does not prove the
+  upstream system acknowledged — an ack dropped during a reconnect leaves
+  exactly that state — and re-acking is the documented retry (§"Best-effort
+  during reconnect"). The cost is a duplicate ack upstream for an alarm that
+  was already acknowledged there.
 - **Native conditions: Acknowledge and AddComment only** — see §"Native alarm
   acknowledge → AVEVA" above. The other methods are refused
   (`BadNotSupported`, no event), and a native ack keeps the condition
@@ -433,9 +462,26 @@ reports nothing.
 - **TimedShelve works (scripted).** `Create()` left `MaxTimeShelved` at 0, and
   the SDK rejects any shelving time above it, so every client TimedShelve
   failed with `BadShelvingTimeOutOfRange`. It is now `int.MaxValue` ms (≈24.8
-  days). The node applies the shelve with no SDK timer of its own; the engine
-  owns the expiry and its Unshelved re-projection reports the one expiry
-  event.
+  days). The engine owns the expiry and its Unshelved re-projection reports
+  the one expiry event.
+- **`UnshelveTime` is the real remaining time** (Gitea #597). Both the method
+  path and the projection used to apply a timed shelve with `shelvingTime 0`,
+  which the SDK reads as `MaxTimeShelved` — so every timed shelve advertised
+  ≈24.8 days remaining. The method now applies the requested duration, and the
+  engine's projection carries its expiry (`AlarmConditionSnapshot.UnshelveAtUtc`),
+  so `ShelvingState/UnshelveTime` counts down to the engine's expiry whichever
+  path shelved it (the AdminUI `/alerts` timed shelve included). This arms the
+  SDK's own unshelve timer at the real instant; it changes no node state and
+  only routes an `Unshelve` (user `system`) back to the engine — a no-op if the
+  engine's 5 s expiry sweep got there first, otherwise it simply lands the
+  expiry on time.
+- **Accepted, not fixed — the SDK's `EventsMonitored` unit for late conditions**
+  (Gitea #597 item 6, from the #586 review). The SDK's `AreEventsMonitored`
+  counter never reaches a condition materialised under a folder that already had
+  an event subscriber. Our own reporting does not depend on it (above); the one
+  thing it still gates is the SDK's method **audit** event, and only while the
+  server is auditing — which no configuration in this repo enables. Closed as
+  accepted.
 - Method **audit** events (`AuditConditionAcknowledgeEventType`, …) are still
   the SDK's, delivered only while the server is auditing over an encrypted
   channel.

docs/ScriptedAlarms.md

@@ -358,7 +358,7 @@ On allow, the handler publishes a `Commons.OpcUa.AlarmCommand` (containing comma
 
 ### Delta-gate de-duplication
 
-`WriteAlarmCondition` fires a Part 9 condition event only when the incoming state differs from the node's current live state. For an OPC UA method call (Acknowledge, Confirm, AddComment, the shelve methods, Enable/Disable) the SDK applies the new state to the node, and the node manager then reports **the one** condition event for it from the method path (Gitea #587 — the SDK reports none of its own, since `AutoReportStateChanges` stays false; the shelve methods' state is applied by the node manager, because the SDK's never applies it; a call that changed nothing — e.g. a re-ack — reports nothing). Native (driver-fed) conditions support only Acknowledge and AddComment; their Confirm, shelve and Enable/Disable methods return `BadNotSupported`. The engine's later re-projection of the same transition finds the node already in that state and is suppressed, so each accepted call yields exactly one event. See `docs/AlarmTracking.md` §"One condition event per method call".
+`WriteAlarmCondition` fires a Part 9 condition event only when the incoming state differs from the node's current live state. For an OPC UA method call (Acknowledge, Confirm, AddComment, the shelve methods, Enable/Disable) the SDK applies the new state to the node, and the node manager then reports **the one** condition event for it from the method path (Gitea #587 — the SDK reports none of its own, since `AutoReportStateChanges` stays false; the shelve methods' state is applied by the node manager, because the SDK's never applies it; a call that changed nothing — e.g. an uncommented re-ack — reports nothing; a re-ack carrying a comment reports that comment once, Gitea #597). Native (driver-fed) conditions support only Acknowledge and AddComment; their Confirm, shelve and Enable/Disable methods return `BadNotSupported`, and their Acknowledge is refused with `BadInvalidState` on a node that is not the redundancy Primary (Gitea #597). A timed shelve's `UnshelveTime` counts down to the engine's expiry (the projection carries `UnshelveAtUtc`). The engine's later re-projection of the same transition finds the node already in that state and is suppressed, so each accepted call yields exactly one event. See `docs/AlarmTracking.md` §"One condition event per method call".
 
 ### AdminUI path