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.

src/pipeline/loose_file_reader.cpp

@@ -0,0 +1,47 @@
+#include "pipeline/loose_file_reader.hpp"
+#include "core/logger.hpp"
+#include <fstream>
+#include <filesystem>
+
+namespace wowee {
+namespace pipeline {
+
+std::vector<uint8_t> LooseFileReader::readFile(const std::string& filesystemPath) {
+    std::ifstream file(filesystemPath, std::ios::binary | std::ios::ate);
+    if (!file.is_open()) {
+        return {};
+    }
+
+    auto size = file.tellg();
+    if (size <= 0) {
+        return {};
+    }
+
+    std::vector<uint8_t> data(static_cast<size_t>(size));
+    file.seekg(0, std::ios::beg);
+    file.read(reinterpret_cast<char*>(data.data()), size);
+
+    if (!file.good()) {
+        LOG_WARNING("Incomplete read of: ", filesystemPath);
+        data.resize(static_cast<size_t>(file.gcount()));
+    }
+
+    return data;
+}
+
+bool LooseFileReader::fileExists(const std::string& filesystemPath) {
+    std::error_code ec;
+    return std::filesystem::exists(filesystemPath, ec);
+}
+
+uint64_t LooseFileReader::getFileSize(const std::string& filesystemPath) {
+    std::error_code ec;
+    auto size = std::filesystem::file_size(filesystemPath, ec);
+    if (ec) {
+        return 0;
+    }
+    return static_cast<uint64_t>(size);
+}
+
+} // namespace pipeline
+} // namespace wowee