[1.21.1] NullPointerException in CameraMixin.updateCamRotationWhileRiding when opening Create Ponder UI (Sinytra Connector on NeoForge)

[ChrisPalm04]

Crash in Create's Ponder UI due to Splinecart's Camera mixin assuming non-null player entity.

Environment

• Minecraft Version: 1.21.1
• Loader: NeoForge 21.1.219
• Splinecart Version: 0.3.1+1.21.1 (Fabric mod via Sinytra Connector 2.0.0-beta.14+1.21.1)
• Create Version: 6.0.9 (includes Ponder 1.0.81+mc1.21.1)
• Other Mods: Full modlist in crash report below; crash is reproducible with minimal setup (NeoForge + Create + Connector + Splinecart).
• OS: Windows 11
• Java: 21.0.7 (Microsoft OpenJDK)

Steps to Reproduce

1. Install NeoForge 1.21.1.
2. Add Create mod.
3. Add Sinytra Connector and Splinecart (Fabric JAR).
4. Launch and create a new world.
5. Place any Create block (e.g., Mechanical Crafter).
6. Right-click the block and press F (or the keybind) to open Ponder UI.
7. Game crashes immediately during screen render.

Does NOT crash during normal gameplay or riding spline carts—only in Ponder.

Expected Behavior

Ponder UI opens normally, showing the tutorial scene.