Add week and article links to 2026 year archive pages

Author: zhjwpku

src/cn/2026/README.md

@@ -1,3 +1,16 @@
 # 2026 年归档
 
 2026 年 PostgreSQL 周报文章。
+
+## 各周
+
+- [第 06 周](./06/README.md)
+  - [COPY TO 的 JSON 格式：PostgreSQL 原生 JSON 导出](./06/copy-to-json-format.md)
+- [第 05 周](./05/README.md)
+  - [GOO：面向大规模连接问题的贪心连接顺序搜索算法](./05/goo-greedy-join-search.md)
+  - [执行器批处理：面向批量的元组处理](./05/executor-batching.md)
+- [第 04 周](./04/README.md)
+  - [PostgreSQL 查询规划器优化：自动 COUNT(*) 转换](./04/planner-count-optimization.md)
+- [第 03 周](./03/README.md)
+  - [扩展统计信息导入/导出功能](./03/extended-statistics-import-functions.md)
+  - [pg_plan_advice：查询计划控制](./03/pg-plan-advice.md)

src/en/2026/README.md

@@ -2,3 +2,15 @@
 
 PostgreSQL Weekly posts for 2026.
 
+## Weeks
+
+- [Week 06](./06/README.md)
+  - [COPY TO with JSON Format: Native JSON Export from PostgreSQL](./06/copy-to-json-format.md)
+- [Week 05](./05/README.md)
+  - [GOO: A Greedy Join Search Algorithm for Large Join Problems](./05/goo-greedy-join-search.md)
+  - [Batching in Executor: Batch-Oriented Tuple Processing](./05/executor-batching.md)
+- [Week 04](./04/README.md)
+  - [PostgreSQL Planner Optimization: Automatic COUNT(*) Conversion](./04/planner-count-optimization.md)
+- [Week 03](./03/README.md)
+  - [Extended Statistics Import/Export Functions](./03/extended-statistics-import-functions.md)
+  - [pg_plan_advice: Query Plan Control](./03/pg-plan-advice.md)