Replace MPQ runtime with loose file asset system

Extract assets from MPQ archives into organized loose files indexed by
manifest.json, enabling fully parallel reads without StormLib serialization.
Add asset_extract and blp_convert tools, PNG texture override support.

tools/asset_extract/path_mapper.hpp

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <string>
+
+namespace wowee {
+namespace tools {
+
+/**
+ * Maps WoW virtual paths to reorganized filesystem categories.
+ *
+ * Input:  WoW virtual path (e.g., "Creature\\Bear\\BearSkin.blp")
+ * Output: Category-based relative path (e.g., "creature/bear/BearSkin.blp")
+ */
+class PathMapper {
+public:
+    /**
+     * Map a WoW virtual path to a reorganized filesystem path.
+     * @param wowPath Original WoW virtual path (backslash-separated)
+     * @return Reorganized relative path (forward-slash separated, original casing preserved)
+     */
+    static std::string mapPath(const std::string& wowPath);
+
+private:
+    // Helpers for prefix matching (case-insensitive)
+    static bool startsWithCI(const std::string& str, const std::string& prefix);
+    static std::string toLower(const std::string& str);
+    static std::string toForwardSlash(const std::string& str);
+    static std::string extractAfterPrefix(const std::string& path, size_t prefixLen);
+};
+
+} // namespace tools
+} // namespace wowee