Patch ver 1.0.15: Mycelial Roots Rendering Performance Overhaul

Summary: The hyphal network that grows across the map is now drawn much more efficiently. Instead of sending each thread to the GPU one at a time, all threads of the same type are bundled together and drawn in a single pass. This eliminates hundreds of redundant operations per frame, especially noticeable in late-game networks with many active roots.

Changes:

1. All network threads are now drawn in a few grouped passes instead of one by one
2. Branches, twigs, live threads, and fading threads each get their own batch
3. No visible changes — the network looks and animates exactly the same
4. Biggest gains appear in late-game networks with hundreds of active threads
5. Reduces CPU overhead significantly during network rendering