epic: Experimental features should have experimental tag

[imtuyethan]

Problem

We force users to go to Settings > Advanced Settings > Turn on Experimental > Turn on each feature to use the latest experimental features. This is an anti-pattern.

Experimental features should be natively built into the application, but denoted with a sublet flag to let users know the feature may be flaky.

Antipatterns
❌ Experimental page in settings
❌ Grouping unrelated experimental features in the same section
❌ Users never discover various features, i.e. "Why doesn't Jan have RAG?"
❌ Users discover it, but can't remember how to turn it off (Quick Ask)
❌ Once experimental moves into stable, it's a very unnatural integration and requires more work, e.g. Quick Ask.

Good patterns
👍 Built into the application on day 1
👍 Visually clear each time users use it, that it is experimental

Experimental features

1. Quick Ask

Figma: https://www.figma.com/design/DYfpMhf8qiSReKvYooBgDV/Jan-App-(3rd-version)?node-id=8522-106723&t=grvrbEHWnoAM254S-4

2. Tools (Retrieval,...)

Figma: https://www.figma.com/design/DYfpMhf8qiSReKvYooBgDV/Jan-App-(3rd-version)?node-id=5119-85461&t=grvrbEHWnoAM254S-4

3. Vulkan

• should this still be experimental at this point? @louis-jan

Figma: https://www.figma.com/design/DYfpMhf8qiSReKvYooBgDV/Jan-App-(3rd-version)?node-id=8522-107553&t=grvrbEHWnoAM254S-4

Note: this page looks a bit different than the current UI is because we have not implemented this yet: #3688

4. Save instruction for new threads

Should roll out to stable releases: #3704

[0xSage]

@imtuyethan can you take a look at my notes in the Description above?

Let's

1. Itemize all the experimental features
2. Have a consistent experimental tag that works for all features
3. Ensure the feature still looks fine once the experimental flag is removed

[imtuyethan]

^ Updated the description with the latest designs