fix(textkit): skip hyphen insertion for CJK characters in line breaking

[matangot]

Summary

CJK (Chinese/Japanese) text gets incorrectly hyphenated with - dashes at line breaks. This happens because breakLines unconditionally inserts a hyphen glyph when breaking at a penalty node, which is correct for Latin scripts but wrong for CJK text where characters wrap naturally without hyphens.

Before

After

The Problem

CJK text has no spaces between characters, so the entire text block becomes a single "word" in the layout engine. When a user's hyphenationCallback splits this into individual characters (the correct approach for CJK), breakLines inserts a - hyphen at every line break point — because it assumes all penalty-node breaks are Latin-style hyphenation.

The Fix

In breakLines, check whether the character at the break point is in the CJK Unicode range. If so, skip the hyphen glyph insertion.

const charAtBreak = attributedString.string.charAt(end - 1);
if (!CJK_RANGE.test(charAtBreak)) {
  line = insertGlyph(line.string.length, HYPHEN, line);
}

Where CJK_RANGE = /[\u3000-\u9fff\uf900-\ufaff\uff00-\uffef]/

This covers:

• Japanese: Hiragana, Katakana, Kanji
• Chinese: CJK Unified Ideographs
• CJK punctuation and fullwidth forms

Korean (Hangul) is excluded as it uses spaces between words and doesn't hit this code path in practice.

Notes

A complete CJK line breaking solution would also include kinsoku (禁則処理) rules in the layout engine — preventing punctuation like 。 ， 、 from starting a new line. That's currently left to userland via hyphenationCallback but could be a follow-up enhancement.

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