ADD - open unique phones by item and hotkey

Register a configurable F1 phone toggle through a server-authoritative open request and retain the selected unique handset by IMEI. Verify usable-item support for every inventory adapter, fail visibly on registration errors, and document the behavior.

sky_phone/config/config.lua

@@ -27,6 +27,7 @@ Config.Command = "phone"
 Config.Phone = {
     Item = "phone",
     Unique = true, -- true: data follows each phone item; false: one persistent phone per character
+    Keybind = "F1", -- false disables the configurable phone key mapping
     AllowMovement = true, -- true: game input stays active while the mobile phone is open
     DevelopmentCommand = true,
     DeviceName = "iFruit Phone",