[BUG] .worktreeinclude patterns with leading `**/` silently match nothing during worktree copy

Bug Description

.worktreeinclude patterns with a leading **/ (e.g. **/.claude/skills/*-local/) silently match nothing during the worktree file copy — the matching gitignored files are not copied into the new worktree, with no warning. The same pattern without the leading **/ works.

The docs (https://code.claude.com/docs/en/worktrees.md, "Copy gitignored files into worktrees") say:

The file uses .gitignore syntax. Only files that match a pattern and are also gitignored are copied, so tracked files are never duplicated.

Under gitignore syntax a leading **/ is valid and means "at any depth including the root" — git check-ignore -v matches these paths against the same pattern. So this is a divergence from the documented contract.

Steps to Reproduce

mkdir repro && cd repro && git init
printf '**/.claude/skills/*-local/\n.claude/worktrees/\n' > .gitignore
printf '**/.claude/skills/*-local/\n' > .worktreeinclude
mkdir -p .claude/skills/foo-local
echo hello > .claude/skills/foo-local/SKILL.md
git add -A && git commit -m init

# sanity: the pattern is valid gitignore and matches
git check-ignore -v .claude/skills/foo-local/SKILL.md
# .gitignore:1:**/.claude/skills/*-local/    .claude/skills/foo-local/SKILL.md

claude -w t1 -p "ok"
ls .claude/worktrees/t1/.claude/skills/foo-local/SKILL.md   # MISSING

# drop the leading **/ and try again
printf '.claude/skills/*-local/\n' > .worktreeinclude
claude -w t2 -p "ok"
ls .claude/worktrees/t2/.claude/skills/foo-local/SKILL.md   # copied

Expected Behavior

**/.claude/skills/*-local/ copies .claude/skills/foo-local/ into the worktree (gitignore semantics: leading **/ matches at any depth, including the repo root), or at minimum a warning is emitted that the pattern matched nothing.

Actual Behavior

Files matching the leading-**/ pattern are silently not copied. The "Copied N files from .worktreeinclude" flow gives no indication the pattern was dropped.

Additional Observations

Tested on v2.1.215 in a larger real repo as well; in the same spawn:

• Exact file paths (foo/.env) — copied
• Single-star globs (frontend/*/.env) — copied
• Trailing-slash directory patterns (infrastructure/local-dev/certs/) — copied
• Leading **/ patterns — not copied, both **/x/*-local/ and **/x/*-local/** forms

The failure doesn't reproduce in the obvious building blocks in isolation, so it appears to be in how they're composed:

• git ls-files --others --ignored --exclude-standard --directory -- '**/.claude/skills/*-local/' lists the directory
• the ignore npm package (tested v5.3.2 and v7.0.5): ignore().add('**/.claude/skills/*-local/').ignores('.claude/skills/foo-local/SKILL.md') returns true

Environment

• Claude Code version: 2.1.215 (native install)
• OS: Linux 6.17.0-40-generic (Ubuntu)
• Shell: bash