bypass the wrapper, go straight to rlgl: 2x more

- skip drawTexture(), submit vertices directly via rl.gl
- manually build quads: rlTexCoord2f + rlVertex2f per corner
- rlBegin/rlEnd wraps the whole entity loop
- ~100k entities at 60fps
- eliminates per-call function overhead
- vertices go straight to GPU buffer
- 20x improvement over baseline