Update blender_thumbnailer.py to read Blender 5.x files

[050011-code]

Summary

Updates blender_thumbnailer.py to read Blender 5.x files.

Refactor blender_thumbnailer.py to improve readability and maintainability. (Declaring this bit as AI made)

Handle file operations more safely.

Tasks Completed

• Platforms Tested:
  • Windows x86
  • Windows ARM
  • macOS x86
  • macOS ARM
  • Linux x86
  • Linux ARM
• Tested For:
  • Basic functionality
  • PyInstaller executable

[050011-code]

Thats on me for not remembering to fix the formating
Looks like I also massacred the attribution

[050011-code]

I'm sorry I was trying to make this pull request on my own fork!

There are still errors as its current state was not meant to be for the original repo

[CyanVoxel]

(Declaring this bit as AI made)

Thank you for your willingness to contribute and fix this issue. Before I start making review comments on this, I'd like to cite our CONTRIBUTING.md's "Unacceptable Code" section:

Unacceptable Code
The following types of code will NOT be accepted to the project:

• [...]
• Code that you do not understand and/or cannot explain (i.e. "vibe coding")

If you're not able to explain why you made specific changes in this (preferably with sources from Blender where applicable) then I'm afraid I won't review this as per our contributing policy. If you do know what you're doing with these changes and are open to me (heavily) scrutinizing the AI-assisted changes, then I'll go ahead with an in-depth review. I wouldn't pester you over exact undocumented byte ranges as long as they work, but every other change I'd want explanations for.

Also, I just pulled this to actually give it a quick test, and it's not working with my Blender 5.x test file:
[info ] [ThumbRenderer][BLENDER][INFO] blender_5.blend Doesn't have an embedded thumbnail.

[CyanVoxel]

Sorry for the conflict caused by #1483, a rebase to main should smooth that out

[CyanVoxel]

@050011-code Any updates on this?

[050011-code]

Hey yes sorry, life has been busy so i haven't done anything on this, i should get free time this weekend to change it

[050011-code]

I've never done this before, do I reopen here or will that not work anymore?

[CyanVoxel]

@050011-code Yes you should be able to reopen here, I'm not sure if you closed this yourself or if something else triggered it to close, but rebasing shouldn't trigger a PR to close

[050011-code]

I must have done something wrong, because it was automatic.
Hopefully reopening won't cause issues

[050011-code]

Haven't fully completed the changes yet, so ignore the checks for now