refactor: 压平数据模型 — 版本为执行主线，需求降为语义标签

核心改动：
- TestCase 主归属 versionId，requirementId 改为可选语义标签
- Bug 新增 versionId（直接挂版本）+ requirementId（可选追溯）
- 新增 calcVersionExecutionStatus() 版本执行态推导函数
  规则：DevTask全部提测→已提测，TestCase全部通过+Bug全关→可发布
- 概览页展示推导出的执行态标签
- BugTab 改为直接 versionId 查询（不再走 testCase→req 链路）
- 统计卡片"参与人员"替换为"未关闭Bug"

心智模型：
  版本（执行线）→ DevTask/TestCase/Bug
  需求（语义线）→ 解释为什么做，不驱动流程

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

apps/web/lib/bug.ts

@@ -6,7 +6,9 @@ export type BugSeverity = 'critical' | 'major' | 'minor' | 'trivial';
 export interface Bug {
   id: string;
   bugNo: string;
+  versionId: string;
   testCaseId: string;
+  requirementId?: string;
   title: string;
   description: string;
   severity: BugSeverity;

apps/web/lib/test-case.ts

@@ -5,7 +5,8 @@ export type TestCaseStatus = 'pending' | 'running' | 'passed' | 'failed' | 'bloc
 export interface TestCase {
   id: string;
   caseNo: string;
-  requirementId: string;
+  versionId: string;
+  requirementId?: string;
   title: string;
   description?: string;
   priority: Priority;

apps/web/lib/version-status.ts

@@ -40,3 +40,66 @@ export function getVersionDisplayStatus(status: VersionStatus, currentStage?: st
   }
   return VERSION_STATUS_LABEL[status];
 }
+
+// === 版本执行态推导 ===
+
+export type VersionExecutionStatus = 'planning' | 'developing' | 'submitted' | 'testing' | 'ready' | 'released';
+
+export const EXECUTION_STATUS_LABEL: Record<VersionExecutionStatus, string> = {
+  planning: '规划中',
+  developing: '开发中',
+  submitted: '已提测',
+  testing: '测试中',
+  ready: '可发布',
+  released: '已发布',
+};
+
+export const EXECUTION_STATUS_COLOR: Record<VersionExecutionStatus, string> = {
+  planning: 'bg-zinc-100 text-zinc-600',
+  developing: 'bg-blue-50 text-blue-600',
+  submitted: 'bg-orange-50 text-orange-600',
+  testing: 'bg-purple-50 text-purple-600',
+  ready: 'bg-emerald-50 text-emerald-600',
+  released: 'bg-zinc-100 text-zinc-500',
+};
+
+export interface ExecutionInput {
+  manualStatus?: VersionStatus;
+  devTasks: { status: string }[];
+  testCases: { status: string }[];
+  bugs: { status: string }[];
+}
+
+export function calcVersionExecutionStatus(input: ExecutionInput): VersionExecutionStatus {
+  const { manualStatus, devTasks, testCases, bugs } = input;
+
+  if (manualStatus === 'released') return 'released';
+  if (manualStatus === 'planned' || manualStatus === 'paused' || manualStatus === 'closed') return 'planning';
+
+  // fallback: 没有 DevTask 则停留 planning
+  if (devTasks.length === 0) return 'planning';
+
+  const allDevDone = devTasks.every((t) => t.status === 'done');
+  const allDevSubmitted = devTasks.every((t) => t.status === 'submitted' || t.status === 'done');
+
+  // 判断是否可发布
+  if (testCases.length > 0) {
+    const allPassed = testCases.every((c) => c.status === 'passed');
+    const allBugsClosed = bugs.every((b) => b.status === 'closed' || b.status === 'rejected');
+    if (allPassed && allBugsClosed) return 'ready';
+  }
+
+  // 测试中（有用例在执行）
+  if (allDevSubmitted && testCases.length > 0) {
+    const hasRunning = testCases.some((c) => c.status === 'running' || c.status === 'passed' || c.status === 'failed' || c.status === 'blocked');
+    if (hasRunning) return 'testing';
+  }
+
+  // 已提测
+  if (allDevSubmitted) return 'submitted';
+
+  // 开发完成但未全部提测
+  if (allDevDone) return 'submitted';
+
+  return 'developing';
+}