`panic` when importing exported `.ply` with `sh-degree=4` — slice index out of range

[iamnotszp]

Description:
I encountered a panic when trying to load an exported .ply file after training with sh-degree=4. The training itself completes without errors, but importing the resulting .ply crashes with a slice index out of range error.

Steps to reproduce:

1. Train a model with SH degree 4:

   brush_app.exe .\output\ --sh-degree 4

   Training runs successfully for 30k steps (~32 minutes), no errors.

2. Try to load the exported .ply with the viewer:

   brush_app.exe .\export_30000.ply --with-viewer

3. The GUI opens but remains empty, and the following panic occurs in the terminal:

   thread 'tokio-runtime-worker' panicked at D:\a\brush\brush\crates\brush-serde\src\import.rs:259:44:
   range end index 46 out of range for slice of length 45
   note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
   

Expected behavior:
The viewer should load and display the trained model without errors.

Actual behavior:
The viewer opens but shows no content, and the command line reports a panic due to a slice index out of range.

Additional information:

• This only happens with sh-degree=4. Training and loading work fine with sh-degree=2 or 3.
• The issue reproduces across multiple custom datasets prepared with COLMAP.
• Using the precompiled Windows release from v0.3.0
• System: Windows 11, AMD Ryzen R6800H, NVIDIA RTX 3060 Laptop (6GB VRAM), 16GB RAM.

Possible cause:
The panic occurs at brush-serde/src/import.rs:259:44, suggesting a mismatch in expected vs. actual slice length when reading SH coefficients for degree 4. This may be a serialization/deserialization bug specific to higher SH degrees.

Workaround:
For now, training with sh-degree=3 or lower works without issues.

Let me know if you need further details or testing. Thanks!

[ArthurBrussee]

This is already fixed at head! I will make a new binary release soon