[Bug]: Windows-style /foo\bar paths open the slash menu #27852

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

packages/shared

Steps to reproduce

In the composer, type a Windows-style path such as cmd /foo\\bar or /Windows\\System32.

Expected behavior

No slash-command menu (same as /tmp/build.sh).

Actual behavior

isPathWord only checks for /, so the picker opens.

Impact

Minor bug or occasional failure

Fix

#27851