Tidy inventory menu and stock preference spacing

[sridharkalaibala]

Remove the extra icon margin on the Inventory expiry link and add a standard one-line gap below the stock-preference dropdown. Item settings now lives under Core Settings Inventory in the pending release. Frontend build, diff and attribution checks pass; no behavior changes.

[github-actions]

Merged to develop. Anyone can test this - you do not need write access.

Try it at https://develop.posnic.io, or run it yourself:

git fetch origin develop && git checkout develop
npm install && npm --prefix api install
npm run dev   # then http://localhost:3000

When you have tested it, say what you did and what happened, and set
QA passed or QA failed. If you cannot set labels, just comment -
a maintainer will.

Reporting that something is broken is as useful as fixing it. It is
better found here than by a shopkeeper.