feat: 开发任务时间字段重构 + 双口径耗时 + 搜索 + 性能优化

核心变更:
- DevTask 字段重构：startDate/dueDate/estimateHours/actualHours 替换为 expectedStartAt/expectedEndAt/actualStartAt/actualEndAt（含时分），预计/实际工时按工作时段（9:00-12:00 + 13:00-18:00）派生计算
- 状态机自动化：到点自动切开发中、未到可手动开干、超期需填延后原因
- 新建 lib/work-hours.ts：calcWorkHours（工作时段过滤）、formatWorkHours（X h（Y 天））、calcTwoMetrics（日历/人力双口径）
- 新建 lib/dev-task-transitions.ts：状态切换守卫
- 三个 Tab 顶部统计：开发任务（预/日历/人力）、测试用例 / Bug（日历 / 人力）；版本概览总人天投入改双行（日历总耗时 / 人力总投入）
- 三个 Tab 加搜索框：300ms debounce + 标题/编号模糊匹配
- 性能优化：requirementIds/categories/requirements/testCases 转 Map/Set 索引、Row 组件 React.memo
- 全局耗时显示统一带天数换算：8h（1天）、11h（1.4天）

新增文件: SearchInput.tsx, useDebouncedValue.ts, work-hours.ts, dev-task-transitions.ts, 设计文档

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/lib/dev-task.ts

@@ -1,4 +1,5 @@
 import type { Priority } from './derive';
+import { calcWorkHours, formatWorkHours, type TimeInterval } from './work-hours';
 
 export type DevTaskStatus = 'todo' | 'in_progress' | 'testing' | 'submitted';
 
@@ -12,18 +13,20 @@ export interface DevTask {
   assigneeId: string;
   reviewerId?: string;
   priority: Priority;
-  estimateHours: number;
-  actualHours: number;
-  startDate?: string;
-  dueDate?: string;
-  completedAt?: string;
+
+  expectedStartAt: string;
+  expectedEndAt: string;
+  actualStartAt?: string;
+  actualEndAt?: string;
+
   status: DevTaskStatus;
   isBlocked: boolean;
   blockReason?: string;
   blockedById?: string;
   predecessorIds?: string[];
   riskLevel?: 'low' | 'medium' | 'high';
-  overdueReason?: string;
+  delayReason?: string;
+  overdueVersionReason?: string;
   createdBy: string;
   createdAt: string;
   updatedAt: string;
@@ -67,28 +70,82 @@ export function calcTaskProgress(task: DevTask): number {
 
 export function calcGroupProgress(tasks: DevTask[]): number {
   if (tasks.length === 0) return 0;
-  const totalEstimate = tasks.reduce((sum, t) => sum + t.estimateHours, 0);
-  if (totalEstimate === 0) return 0;
-  const weighted = tasks.reduce((sum, t) => sum + t.estimateHours * STATUS_PROGRESS[t.status], 0);
+  const totalEstimate = tasks.reduce((sum, t) => sum + getEstimateHours(t), 0);
+  if (totalEstimate === 0) {
+    const sum = tasks.reduce((s, t) => s + STATUS_PROGRESS[t.status], 0);
+    return Math.round(sum / tasks.length);
+  }
+  const weighted = tasks.reduce((sum, t) => sum + getEstimateHours(t) * STATUS_PROGRESS[t.status], 0);
   return Math.round(weighted / totalEstimate);
 }
 
 export function formatHours(hours: number): string {
-  if (hours < 8) return `${hours}h`;
-  const days = Math.floor(hours / 8);
-  const remainder = hours % 8;
-  if (remainder === 0) return `${hours}h（${days}人天）`;
-  return `${hours}h（≈${days}人天）`;
+  return formatWorkHours(hours);
 }
 
-export function calcActualHoursByDates(startDate?: string, completedAt?: string): number {
-  if (!startDate) return 0;
-  const end = completedAt || new Date().toISOString();
-  const startMs = new Date(startDate).getTime();
-  const endMs = new Date(end).getTime();
-  if (isNaN(startMs) || isNaN(endMs) || endMs < startMs) return 0;
-  const diffHours = (endMs - startMs) / (1000 * 60 * 60);
-  return Math.round(diffHours * 2) / 2; // 精确到0.5h
+export function getEstimateHours(task: DevTask): number {
+  if (!task.expectedStartAt || !task.expectedEndAt) return 0;
+  return calcWorkHours(task.expectedStartAt, task.expectedEndAt);
+}
+
+export function getActualHours(task: DevTask, now: Date = new Date()): number {
+  if (!task.actualStartAt) return 0;
+  const end = task.actualEndAt ?? now.toISOString();
+  return calcWorkHours(task.actualStartAt, end);
+}
+
+export interface AggregatedHours {
+  estimate: number;
+  actual: number;
+}
+
+export function aggregateDevTaskHours(tasks: DevTask[], now: Date = new Date()): AggregatedHours {
+  let estimate = 0;
+  let actual = 0;
+  for (const t of tasks) {
+    estimate += getEstimateHours(t);
+    actual += getActualHours(t, now);
+  }
+  return {
+    estimate: Math.round(estimate * 2) / 2,
+    actual: Math.round(actual * 2) / 2,
+  };
+}
+
+export function aggregateActualHoursByAssignee(
+  tasks: DevTask[],
+  now: Date = new Date(),
+): Array<{ assigneeId: string; actualHours: number; taskCount: number }> {
+  const map = new Map<string, { actualHours: number; taskCount: number }>();
+  for (const t of tasks) {
+    const h = getActualHours(t, now);
+    if (h <= 0 && t.status !== 'submitted') continue;
+    const cur = map.get(t.assigneeId) || { actualHours: 0, taskCount: 0 };
+    cur.actualHours += h;
+    cur.taskCount += 1;
+    map.set(t.assigneeId, cur);
+  }
+  return Array.from(map.entries())
+    .map(([assigneeId, v]) => ({
+      assigneeId,
+      actualHours: Math.round(v.actualHours * 2) / 2,
+      taskCount: v.taskCount,
+    }))
+    .sort((a, b) => b.actualHours - a.actualHours);
+}
+
+/**
+ * 抽取每条已开干任务的 [actualStartAt, actualEndAt ?? now] 时间区间
+ * 用于双口径耗时统计（calcTwoMetrics）
+ */
+export function devTaskIntervals(tasks: DevTask[], now: Date = new Date()): TimeInterval[] {
+  const out: TimeInterval[] = [];
+  const nowIso = now.toISOString();
+  for (const t of tasks) {
+    if (!t.actualStartAt) continue;
+    out.push({ start: t.actualStartAt, end: t.actualEndAt ?? nowIso });
+  }
+  return out;
 }
 
 export function generateTaskNo(existingTasks: DevTask[]): string {
@@ -98,3 +155,29 @@ export function generateTaskNo(existingTasks: DevTask[]): string {
   }, 0);
   return `DEV-${String(maxNum + 1).padStart(3, '0')}`;
 }
+
+export function isLegacyTask(t: any): boolean {
+  if (!t || typeof t !== 'object') return false;
+  return (
+    'startDate' in t ||
+    'dueDate' in t ||
+    'completedAt' in t ||
+    'estimateHours' in t ||
+    'actualHours' in t ||
+    'overdueReason' in t
+  );
+}
+
+/**
+ * 兼容函数：按纯小时差计算耗时（保留给 PlanTab/TestCase 体系使用）
+ * DevTask 体系应改用 getActualHours/getEstimateHours 走 calcWorkHours
+ */
+export function calcActualHoursByDates(startDate?: string, completedAt?: string): number {
+  if (!startDate) return 0;
+  const end = completedAt || new Date().toISOString();
+  const startMs = new Date(startDate).getTime();
+  const endMs = new Date(end).getTime();
+  if (isNaN(startMs) || isNaN(endMs) || endMs < startMs) return 0;
+  const diffHours = (endMs - startMs) / (1000 * 60 * 60);
+  return Math.round(diffHours * 2) / 2;
+}