fix(ios): resize single-line TextInput caret to font height

When `lineHeight > fontSize`, UITextField's default caret height
matches `paragraphStyle.maximumLineHeight`, making the cursor visibly
taller than the surrounding glyphs. Override `caretRectForPosition:`
so the caret is sized to `font.lineHeight` and centered vertically
within the full line-box instead.

Author: janicduplessis

packages/react-native/Libraries/Text/TextInput/Singleline/RCTUITextField.mm

@@ -223,7 +223,20 @@ - (CGRect)caretRectForPosition:(UITextPosition *)position
     return CGRectZero;
   }
 
-  return [super caretRectForPosition:position];
+  CGRect rect = [super caretRectForPosition:position];
+
+  // When `lineHeight > font.lineHeight`, UIKit sizes the caret to the full
+  // line-box height, making it visually taller than the surrounding glyph.
+  // Match the caret height to the font's intrinsic line height and center it
+  // so it sits alongside the glyph rather than the whole expanded line-box.
+  NSParagraphStyle *paragraphStyle = _defaultTextAttributes[NSParagraphStyleAttributeName];
+  UIFont *font = _defaultTextAttributes[NSFontAttributeName];
+  if (paragraphStyle && font && paragraphStyle.maximumLineHeight > font.lineHeight) {
+    rect.origin.y += (rect.size.height - font.lineHeight) / 2.0;
+    rect.size.height = font.lineHeight;
+  }
+
+  return rect;
 }
 
 #pragma mark - Positioning Overrides