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/08-keybreak-aggregate/README.md

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+# 08-keybreak-aggregate — Key Break Aggregate
+
+## 电信业务场景
+
+套餐统计。按套餐代码进行key切聚合，计算各套餐的合同数、最大/最小金额、总量等统计信息。
+
+Demonstrates key break processing with four statistical aggregates:
+
+- **COUNT**: Number of records in each key group
+- **MIN**: Minimum VALUE in each group
+- **MAX**: Maximum VALUE in each group
+- **TOTAL**: Sum of VALUE in each group
+
+Same control-break logic as 07-keybreak-summary, extended with
+min/max tracking using IF comparisons.
+
+## Files
+
+| File | Purpose |
+|------|---------|
+| `main-08-keybreak-aggregate.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 |
+| VALUE | PIC 9 | 10 |
+
+## Output Record
+
+| Field | Type |
+|-------|------|
+| KEY | PIC X(10) |
+| COUNT | PIC Z(5)9 |
+| MIN | PIC Z(9)9 |
+| MAX | PIC Z(9)9 |
+| TOTAL | PIC Z(9)9 |