Headless editor crashes in WorldScape shutdown on Windows

[dominicbytes]

Tested versions

• Unmodified master a7e798c (26.3.beta.2.custom_build.a7e798cf7, clean checkout): 6/6 crashes.
• Original test binary at 7d4d64c: 3/3 crashes.
• PR Fix WorldScape editor shutdown crash #1400 build at 01d462e: exits 0 with empty stderr for all three frame counts (built with tests=yes additionally).

System information

Windows 10 Pro 22H2 x64, build 19045.7417; AMD Ryzen 9 7950X3D; headless mode. MSVC 14.51.36231; Python 3.11 / SCons 4.10.1.

Issue description

Found during automated headless testing. Manual GUI closing has not been reproduced here.

Master crashes on shutdown with 0xC0000005 (3221225477). Expected: clean exit 0. Reproduced at 10, 120, and 600 frames, then repeated with a fresh self-contained editor profile: 6/6 crashes, each using a fresh project. No scene, script, or WS3D node is needed.

Matching stack from master:

Node::queue_free (scene/main/node.cpp:3478)
ChannelPackerDialog::`scalar deleting destructor'
Node::_notification (scene/main/node.cpp:304)
WorldScape3DMenu::_notification_backwardv (modules/worldscape_3d/editor/menu.h:46)
predelete_handler (core/object/object.cpp:2353)
SceneTree::_flush_delete_queue (scene/main/scene_tree.cpp:1610)
SceneTree::finalize (scene/main/scene_tree.cpp:862)

Related fix: #1400. Reproduction copied from the PR comment.

Steps to reproduce

1. Build the unmodified master commit above:

python -m SCons platform=windows target=editor arch=x86_64 debug_symbols=yes -j24

2. Create repro/project.godot with the contents below.
3. Run in PowerShell:

& .\bin\redot.windows.editor.x86_64.exe --headless --editor --path .\repro --quit-after 10 --max-fps 60
$LASTEXITCODE

Also reproduced with --quit-after 120 and --quit-after 600.

Minimal reproduction project (MRP)

Only repro/project.godot is needed:

config_version=5
[application]
config/name="Shutdown reproduction"