fix: 新建需求漏传 status 字段导致状态/操作按钮不显示

根因：RequirementModal.handleSubmit 提交时漏传 status，store
createRequirement 也无默认值，落库 status 为 undefined。
page.tsx 的所有操作按钮均按 req.status === '...' 判断，
undefined 不匹配任何分支 → 所有按钮消失；REQ_STATUS_LABEL[undefined]
也是 undefined → 状态列空白。

修复（双兜底，二选一就够，但都改更稳）：
- RequirementModal.tsx: handleSubmit 加 status: initial?.status ?? 'pending_review'
- useRequirementStore.ts: createRequirement 加 status: data.status ?? 'pending_review'

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

apps/web/components/requirement/RequirementModal.tsx

@@ -130,6 +130,7 @@ export function RequirementModal({
       typeId: typeId || undefined,
       priority,
       effort,
+      status: initial?.status ?? 'pending_review',
       creator: initial?.creator || currentUserName || '系统',
       parentId: parentId || undefined,
     });

apps/web/stores/useRequirementStore.ts

@@ -103,6 +103,7 @@ export const useRequirementStore = create<RequirementState>((set, get) => {
       const code = `REQ-${String(requirements.length + 1).padStart(3, '0')}`;
       const newReq: Requirement = {
         ...data,
+        status: data.status ?? 'pending_review',
         id: `req-${Date.now()}`,
         code,
         createdAt: new Date().toISOString().slice(0, 10),