Range Check: UnitXP mode

Added Range Check Mode dropdown (Vanilla / UnitXP) and UnitXP Range Threshold input field under the 40y-Range Check settings in the GUI
In UnitXP mode, UnitInRange bypasses librange entirely and queries UnitXP("distanceBetween") directly with the configured yard threshold
librange scan loop is disabled when UnitXP mode is active — no TargetUnit cycling, no spellbook scanning, no combat interruption
Fixed UnitInRange referencing librange as an undefined local instead of pfUI.api.librange, which caused silent nil returns

api/api.lua

@@ -141,9 +141,22 @@ function pfUI.api.UnitInRange(unit)
     return nil
   elseif CheckInteractDistance(unit, 4) then
     return 1
-  else
-    return librange:UnitInSpellRange(unit)
   end
+
+  -- UnitXP precise mode: skip librange entirely, use direct distance check
+  if C.unitframes.rangecheck_mode == "unitxp" and _G.UnitXP then
+    local threshold = tonumber(C.unitframes.rangecheck_distance) or 40
+    local success, distance = pcall(_G.UnitXP, "distanceBetween", "player", unit)
+    if success and distance then
+      return distance <= threshold and 1 or nil
+    end
+    -- fallthrough to librange if UnitXP fails
+  end
+
+  if pfUI.api.librange then
+    return pfUI.api.librange:UnitInSpellRange(unit)
+  end
+  return nil
 end
 
 -- [ RunOOC ]