fix(ios): center TextInput text when lineHeight > fontSize on Fabric

[janicduplessis]

Summary

On iOS, when a TextInput has lineHeight > fontSize, UIKit misrenders three surfaces:

1. Typed text — glyphs anchor to the bottom of the attributed-string line box instead of centering within it. On Fabric only for multi-line; single-line is affected on both arches.
2. Placeholder — inherits the paragraph style from defaultTextAttributes and sits low, on both Paper and Fabric.
3. Single-line caret — sized to the full paragraph line-box height rather than the font height, visibly taller than the glyph.

The approach depends on which UIKit rendering path draws the affected surface:

UITextView (multi-line) typed text — honors NSBaselineOffsetAttributeName

Call RCTApplyBaselineOffset in RCTTextInputComponentView._setAttributedString: to inject the offset. The helper already ships in Fabric (used by <Text> in RCTTextLayoutManager) but was never wired into the <TextInput> path; Paper fixed this in #38359.

Wiring in the call alone is not enough: each keystroke round-trips UIKit → Fabric state → back, and UIKit's typingAttributes drops NSParagraphStyleAttributeName. _updateState stores the stripped attributedText as an OpaquePointer in TextInputState, which the helper would otherwise read as maximumLineHeight == 0 and return early. Re-seed the paragraph style from defaultTextAttributes on ranges missing it before calling the helper.

Placeholder on both backing views — the UILabel-based draw paths honor NSBaselineOffsetAttributeName

Add the equivalent offset computation to _placeholderTextAttributes on RCTUITextField (used as attributedPlaceholder) and RCTUITextView (used as attributedText of a UILabel subview). Both backing views are shared between Paper and Fabric, so this single change covers both arches.

UITextField (single-line) typed text — the UIFieldEditor draw path does not honor NSBaselineOffsetAttributeName

Instead, override setAttributedText: on RCTUITextField to forward a copy with paragraphStyle's minimumLineHeight/maximumLineHeight zeroed out (and NSBaselineOffsetAttributeName removed) to super. UITextField then renders the line at the font's natural height and its built-in vertical centering positions the glyph correctly in the bounds. The caret rect, which UITextField sizes from the same paragraph-style line box, shrinks to the natural font height as a consequence — no separate caret override is needed.

_defaultTextAttributes (the local ivar) keeps the unmodified paragraph style so the placeholder path still sees the real lineHeight. Yoga's frame-height measurement is also unaffected — this changes only what UITextField uses for per-line rendering.

Changelog

[IOS] [FIXED] - Center typed TextInput text, placeholder, and single-line caret when lineHeight > fontSize.

Test Plan

RN Tester → TextInput → lineHeight baseline renders one single-line and one multi-line TextInput with fontSize: 16, lineHeight: 32. Before: placeholder sits low, typed glyphs anchor to the bottom of the line box, single-line caret overshoots the glyph. After: placeholder and typed text render vertically centered; single-line caret matches the glyph height and sits alongside it.

Paper typed-text behavior is unaffected (the Fabric hunk is isolated to RCTTextInputComponentView._setAttributedString:, and the RCTUITextField.setAttributedText: override is dormant when no paragraphStyle line-height is set). Android is unaffected.

Related: #38359, #39145, #53092.

[github-actions]

Caution

Missing Changelog

Please add a Changelog to your PR description. See Changelog format