Real web-app commit flow, fresh synthetic sample-pick repository on each side.

Before ee90bdc9405d8d4b8ff78ce2133ccb04844298ab
{
  "head": "ab03532 Test User Add picked file",
  "status": "M README.md",
  "cherryPickInProgress": false
}

After afbeb2667241fac2d0e0c5b52f5f4b90117ed964
{
  "head": "b3562dc Test User Main README line",
  "status": "M  README.md\nA  picked.txt",
  "cherryPickInProgress": true
}

After also verified: HEAD equals the pre-action HEAD; README.md and picked.txt both remain staged.
AI-assisted; verified with the tests and tools listed above.