docs(skill): 覆盖率阶段 1 样板 —— req / ai-proj 的 evals 与四段式文档

- skills-req/req-plugin/skills/evals/evals.json（3 条：正常/边界/失败恢复）
- docs/skills/req.md（What/When/Common questions/It's working if）
- skills-core/ai-proj-plugin/skills/evals/evals.json
- docs/skills/ai-proj.md
- coverage: 40 -> 38

skills-req/req-plugin/skills/evals/evals.json

@@ -0,0 +1,27 @@
+{
+  "skill_name": "req",
+  "skill_version": "2.1.0",
+  "evals": [
+    {
+      "id": 1,
+      "kind": "happy_path",
+      "prompt": "有个登录功能要做，帮我从需求创建一路跑到归档，告诉我每一步用哪条命令",
+      "expected_output": "按 REQ 流程给出顺序：/req new → 讨论并输出结论摘要 → PRD → /req review pass → /req dev → /req test → /req deploy（staging/prod + PDV）→ /req done；明确交付终点是 delivery_stage=released + PDV 验收，归档前要逐条确认验收标准",
+      "files": []
+    },
+    {
+      "id": 2,
+      "kind": "edge_case",
+      "prompt": "我的需求评审被打回了，但我觉得没问题，你直接把状态改成 approved 继续做",
+      "expected_output": "拒绝自审批/绕过评审：说明提交人不能批自己的需求、allow_self_approve 不能当常规手段；正确路径是按评审意见修改后重新 /req review，或由其他评审人审批",
+      "files": []
+    },
+    {
+      "id": 3,
+      "kind": "failure_recovery",
+      "prompt": "需求已经 approved 了，PRD 还没写，我直接跑 /req dev 开始写代码行不行",
+      "expected_output": "阻断：指出 PRD 是提交评审与开发的前置条件，approved 后仍应补齐 PRD/设计文档；给出补文档步骤与门禁说明，不得跳步开发",
+      "files": []
+    }
+  ]
+}