Add frontend production project

engine/Age.Engine.Frontend/GodotTimelineLog.cs

@@ -0,0 +1,72 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Text.Json;
+
+/// <summary>Diagnostic-only synchronized JSONL stream for correlating VM execution, host waits/audio,
+/// and compositor object changes. All producers share one lock, so event order is unambiguous even though
+/// the VM and compositor run on different threads.</summary>
+public sealed class GodotTimelineLog : System.IDisposable
+{
+    private readonly object _lock = new();
+    private readonly StreamWriter _writer;
+    private long _sequence;
+    private int _frame;
+    private long _nowMs;
+    private string _script = "<startup>";
+    private int _offset = -1;
+    private int _opcode = -1;
+    private string _state = "starting";
+    private bool _disposed;
+
+    public GodotTimelineLog(string path)
+    {
+        var dir = Path.GetDirectoryName(path);
+        if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
+        _writer = new StreamWriter(path) { AutoFlush = true };
+        Record("start", new() { ["transition"] = "surface-alpha-lifecycle" });
+    }
+
+    public void SetFrame(int frame, long nowMs)
+    {
+        lock (_lock) { _frame = frame; _nowMs = nowMs; }
+    }
+
+    public void Step(string script, int offset, int opcode, int depth)
+    {
+        lock (_lock)
+        {
+            _script = script; _offset = offset; _opcode = opcode; _state = "running";
+            WriteLocked("step", new() { ["depth"] = depth });
+        }
+    }
+
+    public void State(string state, Dictionary<string, object?>? detail = null)
+    {
+        lock (_lock) { _state = state; WriteLocked(state, detail); }
+    }
+
+    public void Event(string kind, Dictionary<string, object?>? detail = null)
+    {
+        lock (_lock) WriteLocked(kind, detail);
+    }
+
+    private void Record(string kind, Dictionary<string, object?>? detail)
+    {
+        lock (_lock) WriteLocked(kind, detail);
+    }
+
+    private void WriteLocked(string kind, Dictionary<string, object?>? detail)
+    {
+        if (_disposed) return;
+        var row = new Dictionary<string, object?>
+        {
+            ["seq"] = ++_sequence, ["kind"] = kind, ["frame"] = _frame, ["now_ms"] = _nowMs,
+            ["script"] = _script, ["offset"] = _offset < 0 ? null : $"0x{_offset:x}",
+            ["opcode"] = _opcode < 0 ? null : $"0x{_opcode:x}", ["vm_state"] = _state,
+        };
+        if (detail != null) foreach (var kv in detail) row[kv.Key] = kv.Value;
+        _writer.WriteLine(JsonSerializer.Serialize(row));
+    }
+
+    public void Dispose() { lock (_lock) { if (_disposed) return; _disposed = true; _writer.Dispose(); } }
+}