Inconsistent [+AMMO] button behaviour with weapon proficiency

Issue description
If a soldier has a ready non-class-related weapon which they are proficient with because of a personal perk, unloading an ammo item from their inventory and then pressing the [+AMMO] button doesn’t automatically equip the just unloaded ammo from stores, unless you also toggle the appropriate weapon class in the item filter or switch to another soldier and then switch back to previously selected one.

Steps to reproduce

  1. Have a soldier that has ready non-class-related weapon which they are proficient with because of a personal perk (e.g. Berserker with Close Combat Specialist that has a shotgun in one of their ready slots).
  2. Have an ammo item for that weapon in that soldier’s inventory.
  3. Unload that ammo item from soldier’s inventory.
  4. Without switching to another soldier, press the [+ AMMO] button next to that weapon.

Expected result
Spare ammo gets automatically equipped from stores.

Actual result
Nothing happens, although the “whirring” sound associated with equipping/manufacturing the ammo item still gets played.

Proposed solution
Since this is related to a QoL issue that was reported a few times (see this post or this one), and this behaviour isn’t very intuitive, I think it would be beneficial to introduce a so-called “Proficiency filter” that should show all generic items and all items that current soldier is proficient with. This filter should be selected by default when opening up the soldier loadout screen from PERSONNEL menu.

yes, I am a software engineer