fix: simplify date-only due labels

frontend/src/lib/task-due.ts

@@ -161,13 +161,15 @@ export function getTaskDuePresentation(input: {
   const dayDelta = calendarDelta(parsed.date, now)
   const absoluteDateText = absoluteDate(parsed.date, now.getFullYear())
   const absoluteText = input.dueHasTime ? `${absoluteDateText} ${localTime(parsed.date)}` : absoluteDateText
+  const completedDescription = completedRelative(dayDelta)
+  const dateOnlyDescription = dayDelta === 0
+    ? '今天'
+    : dayDelta > 0 ? `还有${dayDelta}天` : `已过期${Math.abs(dayDelta)}天`
   const relativeText = input.completed
-    ? completedRelative(dayDelta)
+    ? (input.dueHasTime ? completedDescription : '已完成')
     : input.dueHasTime
       ? timedRelative(parsed.date.getTime() - input.nowMs)
-      : dayDelta === 0
-        ? '今天'
-        : dayDelta > 0 ? `还有${dayDelta}天` : `已过期${Math.abs(dayDelta)}天`
+      : dayDelta === 0 ? '今天' : `${Math.abs(dayDelta)}天`
   const state: TaskDueState = input.completed
     ? 'completed'
     : input.dueHasTime ? (parsed.date.getTime() < input.nowMs ? 'overdue' : 'neutral') : (dayDelta < 0 ? 'overdue' : 'neutral')
@@ -178,7 +180,7 @@ export function getTaskDuePresentation(input: {
     datetime: parsed.datetime,
     absoluteText,
     relativeText,
-    fullText: `${kind}：${fullAbsolute}，${relativeText}`,
+    fullText: `${kind}：${fullAbsolute}，${input.completed ? completedDescription : input.dueHasTime ? relativeText : dateOnlyDescription}`,
     state,
   }
 }