[FEATURE] Add Traditional Chinese (繁體中文 / zh-TW) localization support

Feature Request

Summary

Please add Traditional Chinese (繁體中文, zh-TW) localization support to Claude Code. Existing i18n requests (#4866, #7233, #22386) and Chinese-specific issues (#15253, #22356) have focused on Simplified Chinese (zh-CN). This issue specifically requests zh-TW as a separate locale.

Why Traditional Chinese deserves its own locale (not just zh-CN)

A common misconception is that Traditional and Simplified Chinese are interchangeable or that one is a subset of the other. Here's why they need separate treatment:

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Traditional vs Simplified Chinese: Same Language, Different Writing Systems

Simplified Chinese (简体字) is a reformed writing system introduced by the Chinese government in the 1950s–1960s to increase literacy and reduce stroke complexity. Many characters were simplified by reducing strokes, replacing components, or using historical shorthand forms.

| Meaning | Traditional | Simplified |
|---------|-------------|------------|
| dragon | 龍 | 龙 |
| country | 國 | 国 |
| learn | 學 | 学 |
| body | 體 | 体 |
| love | 愛 | 爱 |

They represent the same language. The grammar and words are identical — only the character forms differ.

Example sentence:

• Traditional: 我今天去圖書館學習。
• Simplified: 我今天去图书馆学习。
• Meaning: I went to the library to study today.

Regional usage

| Script | Primary Regions |
|--------|----------------|
| Traditional (繁體) | Taiwan, Hong Kong, Macau |
| Simplified (简体) | Mainland China, Singapore |

It's more than character conversion

A better analogy is American English vs British English — same language, different spelling conventions — but more visually extreme because Chinese characters are logographic.

Importantly, there are also vocabulary differences between regions:

| Meaning | Taiwan (Traditional) | Mainland (Simplified) |
|----------|---------------------|-----------------------|
| computer | 電腦 | 电脑 |
| software | 軟體 | 软件 |
| server | 伺服器 | 服务器 |
| video | 影片 | 视频 |

This means a naive character-by-character conversion from zh-CN to zh-TW is not sufficient for a good user experience. Proper zh-TW localization requires region-appropriate terminology.

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Why this matters: Political, Cultural, and Identity Context

The reason many people in Taiwan have strong feelings about their writing system is not purely linguistic. It is tied to history, politics, and cultural identity.

Political history (post-1949 split)

After the Chinese Civil War ended in 1949:

• The PRC (mainland) launched script reform → Simplified Chinese
• The ROC (Taiwan) kept Traditional Chinese

Over time, the writing system became associated with two different political paths:

| Region | Script | Political system |
|--------|--------|-----------------|
| Mainland China | Simplified | PRC |
| Taiwan | Traditional | ROC |

Cultural heritage

Many people in Taiwan believe Traditional characters preserve Chinese cultural heritage better:

• They show etymology and radicals more clearly
• They preserve classical forms used for centuries
• They are closer to historical calligraphy and literature

For many Taiwanese scholars and educators, Traditional characters are seen as 「完整的文化載體」 (a complete cultural carrier).

Identity considerations

In Taiwan's modern context, the writing system intersects with identity:

• Traditional Chinese is part of Taiwanese cultural identity
• Offering only Simplified Chinese to Taiwanese users can feel dismissive
• This is similar to how offering only Brazilian Portuguese to users in Portugal would be suboptimal

Important nuance

This is not universal — opinions vary widely across Taiwanese society, and many Taiwanese can read Simplified Chinese. But when it comes to software localization, users strongly prefer their native script, just as users everywhere prefer their own regional variant.

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What I'm requesting

1. zh-TW as a first-class locale — not derived from zh-CN via automated conversion
2. Region-appropriate terminology — using Taiwan-standard technical vocabulary
3. Scope: CLI interface messages, error messages, help text, permission prompts, and documentation

User impact

• Taiwan has a significant and growing developer community
• Hong Kong and Macau also use Traditional Chinese
• Combined, this represents millions of potential users who would benefit from zh-TW support

References

• Related i18n issues: #4866, #7233, #22386, #2415
• Related zh-CN issues: #15253, #22356
• Related CJK bugs: #2780, #19207, #14838