feat(Resources): Add ResourcePackage system for asset bundling

- Implement ResourcePackageBuilder for creating .xcp packages
- Implement ResourcePackage for reading packaged assets
- Add unit tests for package builder and package reader

engine/include/XCEngine/Resources/ResourcePackage.h

@@ -0,0 +1,100 @@
+#pragma once
+
+#include "ResourceTypes.h"
+#include "../Containers/String.h"
+#include "../Containers/Array.h"
+#include "../Core/Types.h"
+
+namespace XCEngine {
+namespace Resources {
+
+struct PackageFileEntry {
+    Containers::String relativePath;
+    size_t size;
+    Core::uint64 checksum;
+    size_t offset;
+};
+
+class ResourcePackageBuilder {
+public:
+    ResourcePackageBuilder();
+    ~ResourcePackageBuilder();
+
+    bool AddFile(const Containers::String& sourcePath, const Containers::String& relativePath);
+    bool AddDirectory(const Containers::String& sourceDir, const Containers::String& relativeBase = "");
+
+    void SetOutputPath(const Containers::String& path) { m_outputPath = path; }
+    const Containers::String& GetOutputPath() const { return m_outputPath; }
+
+    bool Build();
+
+    float GetProgress() const { return m_progress; }
+    const Containers::String& GetError() const { return m_error; }
+
+private:
+    Core::uint64 CalculateChecksum(const void* data, size_t size);
+    bool WriteHeader(FILE* file, size_t dataOffset);
+    bool WriteManifest(FILE* file);
+    bool WriteData(FILE* file);
+
+    struct FileEntry {
+        Containers::String sourcePath;
+        Containers::String relativePath;
+        size_t size;
+        Core::uint64 checksum;
+        size_t offset;
+    };
+
+    Containers::String m_outputPath;
+    Containers::Array<FileEntry> m_files;
+    float m_progress = 0.0f;
+    Containers::String m_error;
+};
+
+class ResourcePackage {
+public:
+    ResourcePackage();
+    ~ResourcePackage();
+
+    bool Open(const Containers::String& packagePath);
+    void Close();
+
+    bool IsValid() const { return m_isValid; }
+
+    bool Exists(const Containers::String& relativePath) const;
+
+    Containers::Array<Core::uint8> Read(const Containers::String& relativePath) const;
+    size_t GetSize(const Containers::String& relativePath) const;
+
+    void Enumerate(const Containers::String& pattern, Containers::Array<Containers::String>& outFiles) const;
+
+    struct PackageInfo {
+        Containers::String path;
+        Core::uint16 version;
+        size_t fileCount;
+        size_t totalSize;
+    };
+
+    const PackageInfo& GetInfo() const { return m_info; }
+
+private:
+    bool ReadHeader(FILE* file);
+    bool ReadManifest(FILE* file);
+
+    bool m_isValid = false;
+    PackageInfo m_info;
+
+    Containers::String m_packagePath;
+    size_t m_dataOffset;
+
+    struct FileEntryInternal {
+        Containers::String path;
+        size_t size;
+        size_t offset;
+        Core::uint64 checksum;
+    };
+    Containers::Array<FileEntryInternal> m_entries;
+};
+
+} // namespace Resources
+} // namespace XCEngine