Fix Sales Item List button view separation

[No0ne558]

Fix Sales Item List button view separation

• show list and form separately

Fixed bug where Sales Item List button type was showing both the list of items and the selected item's configuration simultaneously.

Root Cause: ListFormZone::Render() was unconditionally calling FormZone::Render() which displayed form fields even when showing the list view.

Solution:

• Modified ListFormZone::Render() to conditionally call FormZone::Render() only when show_list is false (form view)
• Modified ListFormZone::Touch() to not load form fields when selecting items from the list
• Modified ListFormZone::Signal() to load form fields when switching from list to form view via 'change view' signal

Result: List view shows only items; form view shows only configuration fields; switching between views requires explicit 'change view' signal.

This fix brings ListFormZone in line with the pattern established in HardwareZone and affects all ListFormZone-based zones (ItemListZone, etc.).

Files modified:

• zone/form_zone.cc (ListFormZone::Render, Touch, Signal methods)
• docs/changelog.md