docs: M3 收官——E2E 报告与收官总结入档，验收 PASSED

- 28 E2E 烟囱：14/14 场景、契约偏差 0、M3 四条验收标准逐条取证
  （两次不同 limit 全量翻页有序 id 逐位相等、删除前后差集验证、psql 库层互证）
- 29 收官总结：终态对照开工基线（测试 191/272→334/502、契约 18→31 路径冻结、
  ADR 001~021、四容器→六容器 + MinIO）、遗留清单与 M4 方向输入
- iteration-3/index.md 进展看板补建；feature-checklist 新增 M3 第 10~12 节
- 另登记 2 项 E2E 观察项：widthPx/heightPx 恒 null、eventVersion 口径未定型

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

mkdocs.yml

@@ -64,6 +64,7 @@ nav:
           - 29 M2 收官总结: development/iterations/iteration-2/29-m2-summary.md
           - 30 真机补验清单: development/iterations/iteration-2/30-device-verification-checklist.md
       - 第三迭代:
+          - 进展看板: development/iterations/iteration-3/index.md
           - 01 任务分解: development/iterations/iteration-3/01-pm-task-breakdown.md
           - 02 后端技术评估: development/iterations/iteration-3/02-backend-technical-assessment.md
           - 03 Flutter 技术评估: development/iterations/iteration-3/03-flutter-technical-assessment.md
@@ -91,6 +92,8 @@ nav:
           - 25 详情页与互动: development/iterations/iteration-3/25-detail-interactions-report.md
           - 26 发布页与漏斗: development/iterations/iteration-3/26-publish-page-report.md
           - 27 第三波收口: development/iterations/iteration-3/27-wave3-closure.md
+          - 28 E2E 烟囱收官: development/iterations/iteration-3/28-e2e-smoke-report.md
+          - 29 M3 收官总结: development/iterations/iteration-3/29-m3-summary.md
   - API:
       - 契约说明: api/index.md
   - 架构: