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/07-keybreak-summary/README.md

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+# 07-keybreak-summary — Key Break Summary
+
+## 电信业务场景
+
+加入者月汇总。按客户ID进行key切汇总，计算每位客户当月的通话总量和总金额。输出每个客户的汇总记录。
+
+Demonstrates the classic COBOL control-break (key break) pattern:
+
+- Read sorted input file grouped by KEY
+- Compare WS-PREV-KEY to detect key change
+- On key change: write summary (KEY, COUNT, TOTAL) and reset accumulators
+- At end-of-file: write final group summary
+- Accumulate grand total across all groups
+
+## Files
+
+| File | Purpose |
+|------|---------|
+| `main-07-keybreak-summary.cbl` | COBOL program (fixed format) |
+| `data-gen.sh` | Generate sorted test data |
+| `run.sh` | Compile, run, verify output |
+
+## Input Record
+
+| Field | Type | Length |
+|-------|------|--------|
+| KEY | PIC X | 10 |
+| AMOUNT | PIC 9 | 10 |
+
+## Output Record
+
+| Field | Type | Notes |
+|-------|------|-------|
+| KEY | PIC X(10) | Group key |
+| COUNT | PIC Z(5)9 | Record count in group |
+| TOTAL | PIC Z(9)9 | Sum of AMOUNT in group |