add harness framework

Codex/Coding/harness framework cpp/scripts/msvc_harness/adapters/base.py

@@ -0,0 +1,19 @@
+from pathlib import Path
+from typing import Protocol
+
+from ..models import HarnessConfig, ProjectSelection, Toolchain, ValidationPlan
+
+
+class AdapterError(RuntimeError):
+    pass
+
+
+class ValidationAdapter(Protocol):
+    def create_plan(
+        self,
+        root: Path,
+        selection: ProjectSelection,
+        config: HarnessConfig,
+        tools: Toolchain,
+    ) -> ValidationPlan:
+        raise NotImplementedError