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__Syms.h

@@ -0,0 +1,38 @@
+// Verilated -*- C++ -*-
+// DESCRIPTION: Verilator output: Symbol table internal header
+//
+// Internal details; most calling programs do not need this header,
+// unless using verilator public meta comments.
+
+#ifndef VERILATED_VMOD_ADD_SYNC__SYMS_H_
+#define VERILATED_VMOD_ADD_SYNC__SYMS_H_  // guard
+
+#include "verilated.h"
+
+// INCLUDE MODEL CLASS
+
+#include "Vmod_add_sync.h"
+
+// INCLUDE MODULE CLASSES
+#include "Vmod_add_sync___024root.h"
+
+// SYMS CLASS (contains all model state)
+class alignas(VL_CACHE_LINE_BYTES) Vmod_add_sync__Syms final : public VerilatedSyms {
+  public:
+    // INTERNAL STATE
+    Vmod_add_sync* const __Vm_modelp;
+    VlDeleter __Vm_deleter;
+    bool __Vm_didInit = false;
+
+    // MODULE INSTANCE STATE
+    Vmod_add_sync___024root        TOP;
+
+    // CONSTRUCTORS
+    Vmod_add_sync__Syms(VerilatedContext* contextp, const char* namep, Vmod_add_sync* modelp);
+    ~Vmod_add_sync__Syms();
+
+    // METHODS
+    const char* name() const { return TOP.vlNamep; }
+};
+
+#endif  // guard