fix: resolve ui audit bugs

frontend/src/lib/mvp-utils.ts

@@ -93,3 +93,31 @@ export function calendarModeLabel(mode: string) {
 export function shouldToggleRowSwipe(deltaX: number, deltaY: number) {
   return deltaX >= 64 && deltaX > Math.abs(deltaY) * 1.5
 }
+
+export function nextTotalAfterLocalTaskAdd(total: number) {
+  return Math.max(0, Number(total) || 0) + 1
+}
+
+export function formatApiErrorDetail(detail: unknown): string {
+  if (typeof detail === 'string') return detail
+  if (Array.isArray(detail)) {
+    const messages = detail.map((item) => {
+      if (item && typeof item === 'object') {
+        const record = item as Record<string, unknown>
+        const location = Array.isArray(record.loc)
+          ? record.loc.filter((part) => part !== 'body').join('.')
+          : ''
+        const message = typeof record.msg === 'string' ? record.msg : JSON.stringify(record)
+        return location ? `${location}：${message}` : message
+      }
+      return String(item)
+    })
+    return messages.filter(Boolean).join('；') || '请求参数有误'
+  }
+  if (detail && typeof detail === 'object') {
+    const record = detail as Record<string, unknown>
+    if ('detail' in record) return formatApiErrorDetail(record.detail)
+    return JSON.stringify(record)
+  }
+  return '请求失败'
+}

frontend/src/lib/ui-bugfixes.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest'
+import { formatApiErrorDetail, nextTotalAfterLocalTaskAdd } from './mvp-utils'
+
+describe('UI bugfix helpers', () => {
+  it('formats FastAPI validation arrays into readable messages', () => {
+    expect(formatApiErrorDetail([
+      { loc: ['body', 'lunar_day'], msg: 'Input should be less than or equal to 30' },
+      { loc: ['body', 'title'], msg: 'String should have at least 1 character' },
+    ])).toBe('lunar_day：Input should be less than or equal to 30；title：String should have at least 1 character')
+  })
+
+  it('formats nested API detail objects instead of [object Object]', () => {
+    expect(formatApiErrorDetail({ detail: [{ loc: ['body', 'event_date'], msg: 'Input should be a valid date' }] })).toBe('event_date：Input should be a valid date')
+  })
+
+  it('increments the visible total after a local quick-add insert', () => {
+    expect(nextTotalAfterLocalTaskAdd(0)).toBe(1)
+    expect(nextTotalAfterLocalTaskAdd(49)).toBe(50)
+  })
+})