Effects client reconciles pending effects: drop stale wait deadlines and seen keys, emit completion for vanished runs; run_not_active is terminal

skills/rudder-csharp-sdk/reference/scenarios.md

@@ -27,7 +27,9 @@ effect. There is no local plan, no `IPlanStateStore`, and no restore.
 - This SDK does **not** fire a login scenario event (`loginEvent` /
   `player_login` is a web-SDK option only). Trigger login-gated scenarios
   yourself with `TriggerAsync`.
-- An effect with an already-seen `(runId, nodeId)` is not re-emitted.
+- An effect with an already-seen `(runId, nodeId)` is not re-emitted. The
+  seen set is pruned against every pending fetch: keys the server no longer
+  lists are dropped, so the server stays the source of truth.
 - There is no local plan persistence. Pending work lives on the server.
 
 ## `ScenarioService` (`client.Scenario`)
@@ -210,7 +212,9 @@ public sealed class ScenarioFailedEffect
 ```
 
 `OnScenarioCompleted` fires when a callback / completed-counter response has
-no next effect (the run finished all its nodes).
+no next effect (the run finished all its nodes). It also fires when a run
+disappears from the pending list with no keys left for it — the server
+advanced a wait, the run expired, or another device completed it.
 
 ## Reliability
 
@@ -219,7 +223,7 @@ no next effect (the run finished all its nodes).
   `onPurchase`, `onDecline`, `onEnd`, `onClaim`, `onComplete`, `onLevelUp`,
   `onPremiumPurchase`. A non-null `effect` in the response is ingested as
   the next node; a null/missing effect completes the run.
-- `unknown_run`, `run_expired` (`RudderErrorCodes`), and HTTP 404
+- `unknown_run`, `run_expired`, `run_not_active` (`RudderErrorCodes`), and HTTP 404
   (`RudderNotFoundException`) on a callback or counter call **drop that
   run** (forget its seen keys and wait deadlines) and fire
   `OnScenarioFailed`.