perf(worker): launcher-configurable event queue capacity

src/ZB.MOM.WW.MxGateway.Server/Configuration/WorkerOptions.cs

@@ -33,6 +33,18 @@ public sealed class WorkerOptions
     /// </summary>
     public int WriteCompletionWaitMilliseconds { get; init; } = 1500;
 
+    /// <summary>
+    ///     Capacity of the worker's outbound MXAccess event queue, in events.
+    ///     Default 10,000; must be between 1,000 and 1,000,000. This is
+    ///     headroom, not a throttle: the queue has no drop policy, so a burst
+    ///     that fills it faults the session with a <c>QueueOverflow</c> worker
+    ///     fault. Raise it for sessions whose subscription set can outrun the
+    ///     drain loop (large advise sets, slow event consumers). Conveyed to
+    ///     the worker through the <c>MXGATEWAY_EVENT_QUEUE_CAPACITY</c>
+    ///     environment variable.
+    /// </summary>
+    public int EventQueueCapacity { get; init; } = 10000;
+
     /// <summary>The maximum time in seconds for graceful shutdown.</summary>
     public int ShutdownTimeoutSeconds { get; init; } = 10;