R62 Fix A1-A6：请假预览全非工作日处理

server/src/services/leave.js

@@ -140,6 +140,7 @@ function calculateRequestedDaysPreviewByWorkingCalendar({
   startSession,
   endSession,
   calendarDays = [],
+  allowNonWorkingRange = false,
 }) {
   const naturalRequestedDays = calculateRequestedDays({
     startDate,
@@ -184,7 +185,19 @@ function calculateRequestedDaysPreviewByWorkingCalendar({
   }
 
   if (requestedUnits <= 0) {
-    throw buildLeaveValidationError({ leave: "non_working_range" });
+    if (!allowNonWorkingRange) {
+      throw buildLeaveValidationError({ leave: "non_working_range" });
+    }
+
+    return {
+      requestedDays: 0,
+      naturalRequestedDays,
+      holidayDayCount: fromHalfDayUnits(holidayUnits),
+      weekendDayCount: fromHalfDayUnits(weekendUnits),
+      adjustedWorkdayCount: fromHalfDayUnits(adjustedWorkdayUnits),
+      calendarApplied: true,
+      isNonWorkingRange: true,
+    };
   }
 
   return {
@@ -194,6 +207,7 @@ function calculateRequestedDaysPreviewByWorkingCalendar({
     weekendDayCount: fromHalfDayUnits(weekendUnits),
     adjustedWorkdayCount: fromHalfDayUnits(adjustedWorkdayUnits),
     calendarApplied: true,
+    isNonWorkingRange: false,
   };
 }