This pull request significantly improves the handling of empty paragraphs and caret/selection logic in the StyledText class, especially around consecutive newlines and edge cases involving line navigation and caret positioning. It also introduces new APIs for line navigation and value retrieval in result types.

Major improvements include:

StyledText caret and selection improvements

• Improved caret placement and selection logic for empty paragraphs (consecutive newlines), ensuring correct caret rendering and navigation in these cases, and fixing several bugs related to caret position at the end of text or on empty lines. [1] [2] [3] [4]
• Refactored getGlyphIndexAtPosition to better handle clicks on empty lines and paragraphs, and to use a more robust line selection algorithm. [1] [2] [3]
• Added two helper methods, findParagraphNewlinePosition and findParagraphNewlinePositionByIndex, to reliably map between visual lines/paragraphs and character indices for newlines. [1] [2]

New API and navigation features

• Introduced getGlyphIndexOnAdjacentLine for moving the caret vertically between visual lines, treating soft-wrapped and explicit lines equivalently. [1] [2]
• Improved initialization and tracking of line heights and paragraph offsets to ensure consistent layout and navigation, especially for empty paragraphs. [1] [2] [3] [4] [5] [6]

ResultValue utility

• Added valueOr overloads to ResultValue, supporting both copy and move semantics for retrieving the stored value or a default, improving ergonomics when working with result types.