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/extractor.hpp

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <atomic>
+#include <cstdint>
+
+namespace wowee {
+namespace tools {
+
+/**
+ * Extraction pipeline: MPQ archives → loose files + manifest
+ */
+class Extractor {
+public:
+    struct Options {
+        std::string mpqDir;       // Path to WoW Data directory
+        std::string outputDir;    // Output directory for extracted assets
+        int threads = 0;          // 0 = auto-detect
+        bool verify = false;      // CRC32 verify after extraction
+        bool verbose = false;     // Verbose logging
+    };
+
+    struct Stats {
+        std::atomic<uint64_t> filesExtracted{0};
+        std::atomic<uint64_t> bytesExtracted{0};
+        std::atomic<uint64_t> filesSkipped{0};
+        std::atomic<uint64_t> filesFailed{0};
+    };
+
+    /**
+     * Run the extraction pipeline
+     * @return true on success
+     */
+    static bool run(const Options& opts);
+
+private:
+    static bool enumerateFiles(const Options& opts,
+                               std::vector<std::string>& outFiles);
+};
+
+} // namespace tools
+} // namespace wowee