feat: init mlkem project with Verilator test framework

- sync_rtl/common/: skid_buffer, pipeline_reg, defines (valid/ready)
- sync_rtl/mod_add/: modular adder example with Verilator C++ TB
- test_framework/: Python-driven Verilator compile/sim/compare pipeline
- test_framework/modules/mod_add/: 50-vector test plan, full鏈路 PASS
- .trellis/spec/: RTL and test_framework conventions documented

obj_dir/Vmod_add_sync__pch.h

@@ -0,0 +1,27 @@
+// Verilated -*- C++ -*-
+// DESCRIPTION: Verilator output: Precompiled header
+//
+// Internal details; most user sources do not need this header,
+// unless using verilator public meta comments.
+// Suggest use Vmod_add_sync.h instead.
+
+#ifndef VERILATED_VMOD_ADD_SYNC__PCH_H_
+#define VERILATED_VMOD_ADD_SYNC__PCH_H_  // guard
+
+// GCC and Clang only will precompile headers (PCH) for the first header.
+// So, make sure this is the one and only PCH.
+// If multiple module's includes are needed, use individual includes.
+#ifdef VL_PCH_INCLUDED
+# error "Including multiple precompiled header files"
+#endif
+#define VL_PCH_INCLUDED
+
+
+#include "verilated.h"
+
+#include "Vmod_add_sync__Syms.h"
+#include "Vmod_add_sync.h"
+
+// Additional include files added using '--compiler-include'
+
+#endif  // guard