feat(tenstorrent): map Backend graph capture onto ttnn mesh-trace

src/vt/tenstorrent/tenstorrent_backend.cpp

@@ -15,9 +15,11 @@
 //     CommitDevice) so the matmul/norm/silu chain can skip host
 //     download+reupload between ops. UnifiedMemory() remains false — the real
 //     hardware property.
-//   * `SupportsGraphCapture()` stays FALSE. tt_metal trace capture
-//     (begin_trace_capture/end_trace_capture/replay_trace) is the eventual
-//     mapping the spec already names; not implemented here.
+//   * `SupportsGraphCapture()` is TRUE: maps onto ttnn mesh-trace capture
+//     (begin_trace_capture / end_trace_capture / execute_trace) via free
+//     functions in tenstorrent_ops.cpp. Capture still requires fixed device
+//     buffers and a warmed program cache — same class of contract as CUDA
+//     graphs (see BeginCapture notes on the CUDA backend).
 //   * `UnifiedMemory()` is `false`: this is the real hardware property (a
 //     discrete card over PCIe), independent of this W0's host-staging
 //     implementation detail above. It also means op_provider.h's portable CPU
@@ -63,6 +65,15 @@ class TenstorrentBackend final : public Backend {
   // optional device shadow (ops TU) is the residency model; the CPU reference
   // tier stays gated off.
   bool UnifiedMemory() const override { return false; }
+
+  // ttnn mesh-trace capture — see Trace* in tenstorrent_device.h / ops.cpp.
+  bool SupportsGraphCapture() const override { return true; }
+  void BeginCapture(Queue&) override { TraceBeginCapture(); }
+  void EndCapture(Queue&) override { TraceEndCapture(); }
+  void Replay(Queue&) override { TraceReplay(); }
+  void* EndCaptureGraph(Queue&) override { return TraceEndCaptureGraph(); }
+  void ReplayGraph(Queue&, void* graph) override { TraceReplayGraph(graph); }
+  void DestroyGraph(void* graph) override { TraceDestroyGraph(graph); }
 };
 
 struct Registrar {

src/vt/tenstorrent/tenstorrent_device.h

@@ -50,4 +50,20 @@ void MarkHostWritten(void* host);
 // device-resident results without every op writing host eagerly.
 void EnsureHostBytes(void* host);
 
+// ---- ttnn mesh-trace capture (Backend graph-capture mapping) --------------
+// Maps vt::Backend::{BeginCapture,EndCapture,Replay} onto
+// ttnn::operations::trace::{begin,end,execute}_trace_capture. Implemented in
+// tenstorrent_ops.cpp so the backend TU stays free of ttnn headers.
+//
+// Contract (same class as CUDA graphs): every op between Begin and End must
+// stay async on the mesh CQ with fixed device buffers; host Ensure/Download
+// and fresh program compiles during capture are illegal and will throw.
+// Warm the program cache with an identical shape before BeginCapture.
+void TraceBeginCapture();
+void TraceEndCapture();           // stores the default single-slot replay id
+void TraceReplay();               // replay the single-slot id
+void* TraceEndCaptureGraph();     // returns an opaque MeshTraceId* (caller owns)
+void TraceReplayGraph(void* graph);
+void TraceDestroyGraph(void* graph);
+
 }  // namespace vt::tenstorrent