ScreenWithStyles is returned by Screen::with_styles but cannot be named outside the crate

[vyncint]

Today — Screen::with_styles() returns ScreenWithStyles<'_> (screen.rs:1867). The type is pub (screen.rs:2037) but lives in the private mod screen (lib.rs:114) and is not in the crate's re-export list (lib.rs:127). It is therefore reachable but unnameable from outside the crate: a consumer can call .with_styles() and pass the result straight to insta, but cannot store it in a struct field, return it from a helper, or write fn f(s: ScreenWithStyles).

Fix. Add ScreenWithStyles to pub use screen::{…} with a one-line doc pointing at Screen::with_styles. Additive.

Done when

• termlens::ScreenWithStyles names the type from a consumer crate (a doctest proves it).