refactor(godot): report subroutines via GodotTraceSink, not the IHost queue

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

godot/GodotAdvHost.cs

@@ -42,12 +42,6 @@ public sealed class GodotAdvHost : IHost
     // called from the main thread (click) or the selftest auto-clicker
     public void SignalInput() { if (_gate.CurrentCount == 0) _gate.Release(); }
 
-    // Records each call-script the VM dispatches (runs on the VM thread, so collect thread-safely and
-    // let the main thread report it — Godot drops GD.Print from background threads).
-    public readonly System.Collections.Concurrent.ConcurrentQueue<long> Dispatched = new();
-    public void CallScript(long id) => Dispatched.Enqueue(id);
-    public void OnStub(int opcode) { }
-
     // ---- texture ops (run on the VM thread; marshal Godot node work to the main thread) ----
     public void CreateTexture(int slot, int width, int height) { _slotBmp[slot] = null; _slotDims[slot] = (width, height); }
 

godot/GodotTraceSink.cs

@@ -0,0 +1,16 @@
+using System.Collections.Concurrent;
+using Age.Engine.Diagnostics;
+
+// Frontend-side trace consumer. Runs on the VM background thread, so it just queues the dispatched
+// call-script ids; the main thread drains them (Godot drops GD.Print from background threads). This
+// replaces the old IHost.CallScript -> GodotAdvHost.Dispatched hack: subroutine visibility is now an
+// engine fact delivered over the trace seam.
+public sealed class GodotTraceSink : ITraceSink
+{
+    public bool TracingSteps => false;
+    public readonly ConcurrentQueue<long> CallScripts = new();
+    public void Emit(in TraceEvent e)
+    {
+        if (e.Kind == TraceEventKind.CallScript) CallScripts.Enqueue(e.Id);
+    }
+}

godot/Main.cs

@@ -19,6 +19,7 @@ public partial class Main : Godot.Control
     private AudioStreamPlayer _voice = null!;              // interrupt-on-new voice
     private VirtualMachine _vm = null!;
     private GodotAdvHost _host = null!;
+    private GodotTraceSink _trace = null!;
     private volatile bool _done;
     private bool _ended;
     private bool _selftest;
@@ -102,7 +103,8 @@ public partial class Main : Godot.Control
         if (_selftest) (script, provider) = BuildSelfTestScene(table);
         else { script = Sys4Loader.Load(Paths.Scripts()[scene.ToUpperInvariant() + ".BIN"], table); provider = Sys4ScriptProvider.Load(table); }
         _host = new GodotAdvHost(this, ResourceMap.Load(), scene);
-        _vm = new VirtualMachine(script, table, _host, null, provider);
+        _trace = new GodotTraceSink();
+        _vm = new VirtualMachine(script, table, _host, null, provider, _trace);
         foreach (var (addr, val) in seeds) _vm.Globals[addr] = val;   // seed initial state before running
         _ = Task.Run(() => { _vm.Run(); _done = true; });
 
@@ -203,7 +205,7 @@ public partial class Main : Godot.Control
     private void ReportSubroutines()
     {
         var ids = new List<long>();
-        while (_host.Dispatched.TryDequeue(out var id)) ids.Add(id);
+        while (_trace.CallScripts.TryDequeue(out var id)) ids.Add(id);
         if (ids.Count == 0) { GD.Print("[subroutines] none dispatched on this path"); return; }
         var distinct = new List<string>();
         foreach (var id in ids) { var h = "0x" + id.ToString("x"); if (!distinct.Contains(h)) distinct.Add(h); }