Meta Issue: make sure that skore brings benefits / is usable in plain vscode / jupyter

[GaelVaroquaux]

Is your feature request related to a problem? Please describe.

Right now, the whole user experience of skore assumes that we are going to use the skore UI (I don't remember how its called). But this is not currently how data scientists work, and they need some where to start.

Data scientists do interactive work in notebooks or vscode (or other environments, those are just the two most popular). We need to find a way for the usage of score to be beneficial very quick in such an environment.

Here is a screenshot of me trying to get some useful information from the CrossValidationReporter:

I struggle to get what I want, which is the report on my cross validation. I have instantiated a skore project to try to see if it would give me a report, though this is not what I was interested in in the short term.
Knowing the discussions around skore, I understand that I probably need to start the server, but nothing on the screen tells me to do it. I am not guided through the process.

Describe the solution you'd like

As a user, I need to find easy ways of getting benefit (eg having the report), without reading the docs.

We should probably consider giving value (showing easily the report) without the skore UI, so that people install us and start using the tool

Summary: For me, it means that when I run in my normal workflow (ie jupyter notebook, or vscode), I get some output that gives me the values that I'm interested in, namely the different scores computed

[glemaitre]

If I put together:

• the current issue
• the issue mentioned in: skore.Project should expose ML features (e.g. CrossValidationReporter, etc.) directly #949
• the issue mentioned in: skore.show_activity() a simple helper function to get users started #1002

I would be really happy as a user to write:

# %%
proj = skore.create()
reporter = proj.CrossValidationReport(estimator, X, y)

# %%
reporter.plot.roc()

and get the reporting activity happening that means:

• # %% should trigger the equivalent of the skore.show_activity() from @GaelVaroquaux or the a kind of skore.launch() that start the UI within VS Code or a browser next to my notebook
• since the call done with proj, having a callback to get sync information between the UI windows and the activity happening the reporter.
• I can continue using my reporter object afterwards if I don't want to use the UI.