Add optional native resource pack export

[e1e5en-gd]

Fixed #77

Project Settings → Build → Pack native resources (experimental)

The setting is stored in the project file:

packNativeResources: true

How it works:

• exported assets/ and lua/ files are collected into game.pak;
• each entry stores its logical path, offset, size, XOR key and byte shift;
• file bytes are lightly obfuscated with byte shift + XOR;
• Data::open() first tries ResourcePack;
• if the file exists in game.pak, restored bytes are returned from memory;
• otherwise normal filesystem loading is used.

Export behavior:

• Desktop export writes game.pak next to the executable;
• Android source export writes project/assets/game.pak, so Gradle includes it in APK assets;
• unpacked exported assets/ and lua/ folders are removed after packing;
• Web export is unchanged because it already uses Emscripten .data resource bundling.

This is not strong encryption. It only hides resources from direct folder browsing.

[mokalux]

this is a great PR, I keep using the framework I am using because it has encryption, both code and assets!

I am keeping an eye on this really promising engine 🙋‍♂️.

Good job devs 🎇!

[eduardodoria]

That is a good job. There are something to improve, but I can help with this.