feat: implement phase 1 solver baseline

scripts/validate_workspace.py

@@ -40,10 +40,25 @@ def load_npm_commands(root: Path) -> list[str]:
     return commands
 
 
+def load_cmake_commands(root: Path) -> list[str]:
+    if not (root / "CMakeLists.txt").exists():
+        return []
+
+    build_dir = root / "build"
+    return [
+        f'cmake -S "{root}" -B "{build_dir}"',
+        f'cmake --build "{build_dir}" --config Debug',
+        f'ctest --test-dir "{build_dir}" --output-on-failure -C Debug',
+    ]
+
+
 def discover_commands(root: Path) -> list[str]:
     env_commands = load_env_commands()
     if env_commands:
         return env_commands
+    cmake_commands = load_cmake_commands(root)
+    if cmake_commands:
+        return cmake_commands
     return load_npm_commands(root)
 
 
@@ -54,11 +69,13 @@ def run_command(command: str, root: Path) -> subprocess.CompletedProcess:
         shell=True,
         capture_output=True,
         text=True,
+        encoding="utf-8",
+        errors="replace",
     )
 
 
 def emit_stream(prefix: str, content: str, *, stream) -> None:
-    text = content.strip()
+    text = (content or "").strip()
     if not text:
         return
     print(prefix, file=stream)