docs: M2 收官——E2E 烟囱报告与收官总结入档，验收 PASSED

- 28 E2E 烟囱：11/11 场景全绿、契约偏差 0、四条验收标准全过（真机两项方案 A 挂起）
- 29 收官总结：终态对照开工基线（测试 82/34→191/272、契约 5→18 路径冻结、
  ADR 001~015、生产埋点从零到贯通）、遗留清单与 M3 方向输入
- 看板终态更新

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

mkdocs.yml

@@ -59,6 +59,8 @@ nav:
           - 25 体重疫苗模块: development/iterations/iteration-2/25-weights-vaccines-ui-report.md
           - 26 时间线与提醒页: development/iterations/iteration-2/26-timeline-reminders-report.md
           - 27 第三波收口: development/iterations/iteration-2/27-wave3-closure.md
+          - 28 E2E 烟囱收官: development/iterations/iteration-2/28-e2e-smoke-report.md
+          - 29 M2 收官总结: development/iterations/iteration-2/29-m2-summary.md
   - API:
       - 契约说明: api/index.md
   - 架构: