[Bug]: Non-Latin feature descriptions produce a nameless branch/directory (001-, 004-, ...)

从 .specify/scripts/powershell/create-new-feature.ps1 中的 Get-BranchName 开始，然后比较对应的 Bash 和 Python 实现。使用仅包含 CJK 字符的描述重现空后缀，确定建议的行为中哪一种是可接受的，并添加回归测试以证明生成的分支和目录不再没有名称。

What happened

A feature description written entirely in a non-Latin script produces a branch and directory with no name at all — just the number and a trailing dash. Every such feature looks identical apart from its number.

specify init demo --integration claude

./.specify/scripts/powershell/create-new-feature.ps1 -Json "给倒推引擎加正推能力"
# {"BRANCH_NAME":"001-", ... "specs\\001-\\spec.md"}

./.specify/scripts/powershell/create-new-feature.ps1 -Json "客户邮件审核队列"
# {"BRANCH_NAME":"004-", ... "specs\\004-\\spec.md"}

Resulting tree — two unrelated features, indistinguishable:

specs/
├── 001-/
├── 004-/
└── 005-mail-review-queue/   # same description, but with -ShortName

For comparison, on the same install:

Why this is not the already-known crash

Get-BranchName in create-new-feature.ps1 already carries a comment describing this path — a previous fix stopped it throwing ArgumentNullException and made it return an empty suffix instead, matching the bash and Python twins. That fix is correct as far as it goes: the script no longer dies.

But the outcome it settles on is a directory name that carries no information. The empty suffix is a reasonable internal result; it just isn't a usable name. For a team working in Chinese, Japanese, Korean, Arabic, Hebrew, Thai, Greek, or Cyrillic, this is the default path, not an edge case — every feature they create lands in NNN-.

The root cause is the character class, in two places:

# line 89
$Name.ToLower() -replace '[^a-z0-9]', '-' ...
# line 136
$Description.ToLower() -replace '[^a-z0-9\s]', ' '

Both drop every non-ASCII character, so a CJK description reduces to the empty string before stop-word filtering ever runs.

Suggested directions

Listed roughly by cost; any one of them removes the nameless directory.

1. Warn and point at the escape hatch. -ShortName already works (005-mail-review-queue above). When the computed suffix is empty, print a line saying the description produced no usable branch name and that -ShortName <name> sets one. Cheapest fix, and it turns a silent surprise into a choice.
2. Fall back to something stable instead of nothing. A short hash or timestamp of the description — 001-f3a9c2, 001-20260914 — is still opaque, but at least distinct per feature.
3. Widen the character class. Keep Unicode letters and digits (\p{L}\p{N}) and percent-encode or transliterate what git cannot take. Git branch names do accept UTF-8, so 001-客户邮件审核队列 is a legal ref; whether it is desirable is a separate call, and tooling downstream may not all agree.

(1) alone would have saved the confusion here. (3) is the real fix but needs a decision about non-ASCII refs that is yours to make, not mine.

Environment

• specify-cli 1.0.7.dev0 (git d848fb4), installed via uv tool install
• Windows 11, PowerShell 5.1, Python 3.13.7, git 2.49.0.windows.1
• --script auto-selected powershell

Not PowerShell-specific — reproduced on both script backends:

specify init demo-sh --integration claude --script sh
bash .specify/scripts/bash/create-new-feature.sh --json "给倒推引擎加正推能力"
# {"BRANCH_NAME":"001-", ... "specs/001-/spec.md"}