Server-side scenario execution: effects client replaces local engine

- client.Effects: typed effects + completion methods posting scenario callbacks
- client.Scenario reduced to TriggerAsync
- pending polling via Update() pump: 30s heartbeat + wait-deadline checks
- local engine, plan persistence (IPlanStateStore) and resume removed
- RealtimeService and realtime transports removed (relay never deployed)
- dead IPlanScheduler leftover removed
- models regenerated from openapi (ExecutionPlan/BoundaryNode gone, PendingEffect added)

Services/Effects/BattlePassLevelEffect.cs

@@ -0,0 +1,41 @@
+using System.Threading;
+using System.Threading.Tasks;
+using Newtonsoft.Json.Linq;
+
+namespace RudderSdk.Core;
+
+/// <summary>
+/// A scenario battle-pass-level node — a single claimable tier.
+/// <see cref="ClaimAsync"/> posts <c>onComplete</c>, which the server accepts
+/// only once the player has reached the node's configured level.
+/// </summary>
+public sealed class BattlePassLevelEffect
+{
+    private readonly EffectHandle _handle;
+
+    internal BattlePassLevelEffect(EffectHandle handle) => _handle = handle;
+
+    /// <summary>Run id.</summary>
+    public string RunId => _handle.RunId;
+
+    /// <summary>Scenario id.</summary>
+    public string ScenarioId => _handle.ScenarioId;
+
+    /// <summary>Node id.</summary>
+    public string NodeId => _handle.NodeId;
+
+    /// <summary>The tier level this node claims.</summary>
+    public int Level => _handle.Get("levelNumber", 0);
+
+    /// <summary>Node data payload.</summary>
+    public JObject Data => _handle.Data;
+
+    /// <summary>Reads a typed value from the node data.</summary>
+    public T Get<T>(string key, T defaultValue = default!) => _handle.Get(key, defaultValue);
+
+    /// <summary>Claims this tier; posts <c>onComplete</c>.</summary>
+    public Task ClaimAsync(CancellationToken cancellationToken = default) => _handle.CompleteAsync("onComplete", cancellationToken);
+
+    /// <summary>Claims this tier (fire-and-forget).</summary>
+    public void Claim() => _handle.Complete("onComplete");
+}