Add Distinct Visual Elements for Non-Production Versions (icon, splash screen, etc)

[SableRaf]

Non-production builds for Processing currently look mostly identical to official releases, making it difficult to recognize at a glance that you're using a non-production version. This could lead to confusion among testers and contributors, and create mix-ups when reporting issues.

I suggest we introduce distinct visual markers for pre-release versions (test, beta, dev, or nightly builds). This will help users immediately recognize they are running a non-production version of Processing.

Proposed Changes

1. App Icon – Use an alternate icon for non-production builds, such as adding a yellow ribbon with Test, Beta, or Dev depending on the build type.
2. Splash Screen – Include a clear indicator that the user is running a pre-release version.
3. Version Label in UI – Add a visible label (e.g., "Test Build," "Beta," "Nightly") in the title bar.
4. Instructions for testing – Include a README in test builds only with specific instructions for testing.

[SableRaf]

Making separate issues for this particular topic may be overkill but I wanted to test Github's new sub-issues 😃

[Stefterv]

I was wondering where the giant list came from :)

[Stefterv]

For the beta we cannot really use an indicator in the way we've done it so far. The beta's have been release assets and have not been re-compiled for the final release. I assume there would be no variance in building it again but the current setup is not really conducive to doing it.

[Stefterv]

In the gradle version I've already made it so that you can run the released version and the build version at the same time. Maybe we can look into having a different settings folder etc...

Also still thinking of creating a little helper tool that helps with installing testing versions etc...