feat: show overdue tasks on today view

frontend/src/style.test.ts

@@ -81,7 +81,7 @@ describe('task and habit row decoration', () => {
     expect(app).not.toContain('class="sr-only" :aria-label="node.task.completed')
     expect(app).not.toContain('class="sr-only" :aria-label="subtask.completed')
     expect(app).toContain('class="task-check"')
-    expect(app.match(/class="task-check"/g)?.length).toBe(2)
+    expect(app.match(/class="task-check"/g)?.length).toBe(3)
     expect(app).toContain('class="task-check-mark"')
     expect(css).toContain('.task-check{')
     expect(css).toContain('.task-check-mark{')
@@ -112,6 +112,17 @@ describe('task and habit row decoration', () => {
     expect(css).toContain('.habit-toolbar{')
   })
 
+  it('shows unfinished overdue tasks as a separate list inside Today', () => {
+    expect(app).toContain('const overdueTasks = ref<Task[]>([])')
+    expect(app).toContain("params.set('due_to', isoAtLocalDayOffset(0))")
+    expect(app).toContain("params.set('completed', 'false')")
+    expect(app).toContain('class="overdue-section"')
+    expect(app).toContain('已过期')
+    expect(app).toContain('v-for="node in overdueTaskTree"')
+    expect(css).toContain('.overdue-section{')
+    expect(css).toContain('.overdue-heading{')
+  })
+
   it('keeps Today as a low-noise dashboard with direct empty-state actions', () => {
     expect(app).toContain('class="today-board"')
     expect(app).toContain('todayOpenTasks')