Integrate Refactor solver sources and dual MSVC CMake builds

include/fesa/core/ascii.h

@@ -2,6 +2,7 @@
 #define FESA_CORE_ASCII_H_
 
 #include <cstdint>
+#include <string>
 #include <string_view>
 
 #include "fesa/core/status.h"
@@ -12,6 +13,11 @@ namespace fesa {
 /// @return The lowercase ASCII byte, or the input byte when it is not A-Z.
 char AsciiLower(char value) noexcept;
 
+/// @brief Returns an uppercase ASCII copy without changing other source bytes.
+/// @note Embedded nulls and non-ASCII bytes are preserved without locale
+/// folding.
+std::string AsciiUppercase(std::string value);
+
 /// @brief Compares two byte strings with ASCII-only case folding.
 /// @return True when the strings have equal length and equal ASCII-folded
 /// bytes.