The `cd <path> && ...` extractor matched everything up to the first `&&`
with a greedy regex, so a redirect or extra argument before the `&&` was
swallowed into the structured cwd. `cd /tmp 2>/dev/null && echo ok` became
cwd `/tmp 2>/dev/null`, which failed fs.stat and killed the command before
the shell ran.
Replace the regex with `extractLeadingCdTarget`, a quote/escape-aware
scanner in shell-tokenize.ts that captures exactly one path token and
bails (leaving the command for the shell) when anything else — a redirect,
extra argument, shell expansion, or a non-`&&` separator — precedes the
top-level `&&`.
Fixes#7883
can1357