Fix truncated native PHP copy in What's New modal

[bcotrim]

Related issues

• Follow-up to Add native PHP runtime page to What's New modal #3915 — fixes the truncation reported in review feedback
• Related to RSM-4414

How AI was used in this PR

Used Claude Code (Opus 4.8) to diagnose the truncation, trace the history of the modal's line-clamp behavior, and implement the fix. I confirmed the modal renders every slide's copy in full (no truncation, no scrollbar) in the running app, and ran ESLint + a typecheck on the changed file.

Proposed Changes

The "Faster local sites with native PHP" slide in the What's New modal was cutting its description off mid-sentence ("…switch between Native…").

The root cause was a fragile rule, not the copy itself: the modal clamped the first slide's description to 5 lines but every other slide to 3. The native PHP copy was written while it was the lead slide; once a Studio Code slide became the new lead (#3924), native PHP dropped into a 3-line slot and its (unchanged) text no longer fit.

Rather than trimming the copy, this gives every slide the same 5-line clamp the intro slide already used — which the fixed-height modal accommodates without scrollbars. That removes the intro-vs-regular distinction that caused the regression, so future copy tweaks or slide reordering won't silently truncate. It also drops a leftover wrapper element that had no styling. The slide copy is unchanged from trunk.

Thanks to @fredrikekelund for suggesting the all-slides approach over a copy-only fix.

Testing Instructions

1. Run Studio (npm start).
2. Open the What's New modal (app menu → What's New).
3. Page through every slide and confirm each description shows in full with no truncation/ellipsis — in particular, the "Faster local sites with native PHP" slide should end with "…in your site settings."
4. Confirm no scrollbar appears on any slide and the footer buttons stay in place.
5. Verify in both light and dark appearance.

Pre-merge Checklist

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

[wpmobilebot]

📊 Performance Test Results

Comparing fd1d70e vs trunk

app-size

Metric	trunk	fd1d70e	Diff	Change
App Size (Mac)	1311.88 MB	1311.88 MB	0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	fd1d70e	Diff	Change
load	1028 ms	1036 ms	+8 ms	⚪ 0.0%

site-startup

Metric	trunk	fd1d70e	Diff	Change
siteCreation	6516 ms	6509 ms	7 ms	⚪ 0.0%
siteStartup	6470 ms	7022 ms	+552 ms	🔴 8.5%

---

Results are median values from multiple test runs.

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

[fredrikekelund]

The difference in line clamping between the first slide and the subsequent ones seems to have been introduced to prevent scrollbars from appearing. See #1128 (comment)

I can't really trigger a scrollbar even if I change the line clamping to 5 lines. I could see us changing that setting to 5 lines for all slides. This seems like an issue that could easily trip us up in the future, too.

I'll leave that call to you, @bcotrim. This simplistic solution works, too

[bcotrim]

@fredrikekelund I also couldn't replicate the scrollbar, so I removed the conditional number of lines.
Let's keep an eye for any regressions.

I reverted the change back to the original text.