feat: project skeleton, core types and math with transform tests

include/plot/core/status.hpp

@@ -0,0 +1,26 @@
+#pragma once
+#include <plot/core/types.hpp>
+
+namespace plot {
+
+enum class ErrorCode {
+  Ok,
+  InvalidArgument,
+  OutOfMemory,
+  GLFailure,
+  Unsupported,
+  NotImplemented,
+};
+
+/// Never-null human-readable name of an error code.
+const char* to_string(ErrorCode code) noexcept;
+
+/// Result of a fallible operation. Falsy unless `code == ErrorCode::Ok`.
+struct Status {
+  ErrorCode code = ErrorCode::Ok;
+  const char* message = "";
+
+  constexpr explicit operator bool() const noexcept { return code == ErrorCode::Ok; }
+};
+
+}  // namespace plot