Rebased onto origin/main (49128b576). Fixtures moved from
scripts/hooks/ to /tmp/ecc-pr2380-fixtures/ per reviewer feedback.
(Original commit b0e49036 was based on cc6724ee; main has since
refactored spawnShell to use a shellArgs variable and added
PowerShell .sh fallback paths. This rebase adapts the
const result = spawnSync(...) + __rawInput tagging pattern to
all three spawnSync call sites in spawnShell.)
haelyra