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

test_framework/lib/vector_gen.py

@@ -0,0 +1,61 @@
+"""vector_gen.py - Base class for vector generators.
+
+Each module provides a gen_vectors.py that subclasses VectorGenerator.
+The generate_one() method is abstract and must be overridden.
+The write_hex_file() method writes vectors as hex-formatted files.
+"""
+
+import os
+from abc import ABC, abstractmethod
+
+
+class VectorGenerator(ABC):
+    """Base class for test vector generators."""
+
+    @abstractmethod
+    def generate_one(self, params: dict) -> dict:
+        """Generate a single test vector.
+
+        Args:
+            params: Module-specific parameters for vector generation.
+
+        Returns:
+            dict with 'input' and 'expected' keys, each containing a dict
+            of signal_name -> value.
+        """
+        ...
+
+    def write_hex_file(self, vectors: list[dict], filepath: str) -> None:
+        """Write vectors to a hex file.
+
+        Subclasses should override this to match their module's input format.
+        Default: writes each vector on one line, hex values separated by spaces.
+
+        Args:
+            vectors: List of result dicts from generate_one().
+            filepath: Path to write the hex file.
+        """
+        os.makedirs(os.path.dirname(filepath), exist_ok=True)
+        with open(filepath, 'w') as f:
+            for v in vectors:
+                # Default: write input values as space-separated hex
+                inputs = v.get('input', {})
+                hex_vals = [format(val, 'X') for val in inputs.values()]
+                f.write(' '.join(hex_vals) + '\n')
+
+    def write_expected_file(self, vectors: list[dict], filepath: str) -> None:
+        """Write expected results to a hex file.
+
+        Subclasses should override this to match their module's expected format.
+        Default: writes each expected value on one line.
+
+        Args:
+            vectors: List of result dicts from generate_one().
+            filepath: Path to write the expected hex file.
+        """
+        os.makedirs(os.path.dirname(filepath), exist_ok=True)
+        with open(filepath, 'w') as f:
+            for v in vectors:
+                expected = v.get('expected', {})
+                hex_vals = [format(val, 'X') for val in expected.values()]
+                f.write(' '.join(hex_vals) + '\n')