Simplify "What to do with running sites" dialog when quitting Studio

[fredrikekelund]

Related issues

• Fixes STU-1908

How AI was used in this PR

Codex executed the implementation based on detailed instructions from me, informed by @shaunandrews's design spec in STU-1908.

Proposed Changes

#3837 changed the dialog Studio displays when quitting with running sites to look like this:

I argued in #3837 (comment) that this is too complex, and Shaun agreed. This PR changes the dialog to display a shorter text with fewer buttons again, along with a new dropdown in the Studio settings (and in the new agentic UI).

Dialog	Studio settings	Agentic UI settings

Testing Instructions

1. Edit ~/.studio/app.json and remove the quitSitesBehavior prop
2. npm start
3. Start at least one site
4. Quit Studio
5. Ensure that you see a dialog asking you what to do with the running sites
6. Pick one of the choices and ensure it works (sites are running or are stopped after the app closes)
7. npm start again
8. Open the Studio settings, ensure the new setting is there and works as expected (you can check app.json to verify that the setting is persisted)
9. ENABLE_AGENTIC_UI=true npm start
10. Click your profile name in the bottom left corner to open the settings view
11. Ensure the new setting is there and works as expected (you can check app.json to verify that the setting is persisted)

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing 1b4bd11 vs trunk

app-size

Metric	trunk	1b4bd11	Diff	Change
App Size (Mac)	1352.85 MB	1350.67 MB	2.18 MB	🟢 -0.2%

site-editor

Metric	trunk	1b4bd11	Diff	Change
load	1117 ms	1047 ms	70 ms	🟢 -6.3%

site-startup

Metric	trunk	1b4bd11	Diff	Change
siteCreation	6472 ms	6532 ms	+60 ms	🔴 0.9%
siteStartup	2391 ms	2396 ms	+5 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[wojtekn]

This is a good improvement - the previous dialog had too many choices and was hard to read.

I tested it, and it works in general, but one case does not seem to be correct:

1. I have "Ask every time" selected
2. I quit Studio
3. In the dialog, I choose "Stop site", and "Remember my choice"
4. I restart Studio

By selecting "stop site", I would expect that my site will be stopped, and will be kept stopped, as dialog doesn't say anything about auto-start.

Instead, when I reopen Studio, the site starts automatically. Settings show "Stop, restart on next launch" option as selected.

I think that having "Stop sites" saved in my case would be more logical.

@shaunandrews any thoughts?

[wojtekn]

I pushed the mentioned changes to the branch.