i18n audit: contentDescription set inside a semantics {} lambda is still invisible (a11y copy stays English) #571

Follow-up to #540 / #558. #558 fixed the conditional-literal blind spot (Text(if x "a" else "b")), but a different axis remains invisible: a UI-text kwarg set inside a lambda.

The gap

ANDROID_KWARG_PATTERN includes contentDescription, and the audit catches it as a normal call argument:

Foo(contentDescription = if (hr) "Recovery ready" else "Recovery, no data yet")   // CAUGHT

But the standard Compose accessibility idiom sets it inside a semantics {} lambda, and that brace is opaque (correctly — semantics isn't a transparent keyword, so the anti-489-explosion split skips it):

Modifier.semantics { contentDescription = if (hr) "Recovery ready" else "Recovery, no data yet" }   // MISSED

Verified against scan_android() on merged main: the plain-arg form is flagged, the semantics {} form is not, and the strings pass is_probably_ui_text — so it's a genuine scan gap, not the filter.

Why it matters

This is exactly the real bug behind the earlier review finding: CoupledScreen.kt builds three hardcoded-English a11y strings ("Recovery calibrating, $n of $seed nights", "Recovery, no data yet", …) and assigns them via .semantics { contentDescription = a11y }. A German TalkBack user hears English there. The Apple twin localizes it (String(localized:)); Android doesn't. After #558 the audit still reports clean for this class, so the baseline can't track it and it silently never gets localized.

Suggested fix

A targeted rule rather than reopening all braces: scan contentDescription = (and any other genuine UI-text kwarg) even inside a trailing/semantics lambda. That catches the a11y idiom without sweeping unrelated lambda content back in (the case #558 deliberately kept opaque). A regression test should assert Modifier.semantics { contentDescription = if (x) "A" else "B" } is flagged while AlertDialog(text = { Column { … } }) still isn't.

Not urgent — no correctness impact, only untranslated a11y copy — but worth tracking so it doesn't hide behind a green audit.