feat: add benchmark-programs — 58 telecom COBOL test programs

作为子目录纳入系统，与核心测试管道协同

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

benchmark-programs/09-db-update/README.md

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+# 09-db-update — Database Update Simulation
+
+## 电信业务场景
+
+客户信息DB更新。使用索引文件模拟关系数据库，实现客户信息的INSERT、UPDATE、DELETE操作。
+
+## Purpose
+Simulates DB update operations (INSERT, UPDATE, DELETE) using GnuCOBOL INDEXED files as a stand-in for EXEC SQL.
+
+## Test Coverage
+1. **INSERT 3 records** — WRITE to indexed file with STATUS check
+2. **Duplicate INSERT** — Attempt key duplicate, expect STATUS 22
+3. **UPDATE** — READ then REWRITE to modify an existing record
+4. **DELETE** — READ then DELETE to remove a record
+5. **Verify** — START + READ NEXT to read back remaining records
+6. **Report** — Summary output to report.txt
+
+## Key Techniques
+- INDEXED file with DYNAMIC access
+- FILE STATUS checking (00=OK, 22=dup, 23=not found, 10=EOF)
+- WRITE / REWRITE / DELETE with INVALID KEY
+- START + READ NEXT for sequential traversal