feat: add agent mode pipeline (orchestrator_jcl)

- Add --mode agent to main.py for jcl-cobol-data-create integration
- New orchestrator_jcl.py: 5-phase pipeline
  Phase 1: Call jcl-cobol-data-create (DeepSeek LLM) to generate JSON test data
  Phase 2: Parse COBOL FD layouts via analyze_fd_layout
  Phase 3: Compile COBOL + subprograms + Java (once)
  Phase 4: Per-group loop: JSON->binary->run COBOL->run Java->compare->report
  Phase 5: Aggregate summary
- Fix orchestrator.py import error (check_coverage from cobol_testgen.coverage)
- Normalize jcl JSON field names (R01-APPL-ID -> R01APPL-ID) for FD layout matching
- Auto-compile subprograms by scanning CALL statements in COBOL source
- Update README.md with agent mode usage and architecture docs
- jcl-cobol-data-create api_client.py: bypass Windows system proxy

orchestrator.py

@@ -10,7 +10,8 @@ from comparator import align_records, compare_field, CobolBinaryReader
 from report import ReportGenerator
 from storage import TestDataBundle
 from config import Config
-from cobol_testgen import extract_structure, generate_data, incremental_supplement, check_coverage
+from cobol_testgen import extract_structure, generate_data, incremental_supplement
+from cobol_testgen.coverage import check_coverage
 from hina import classify_program, gate_check, supplement as strategy_supplement
 
 logger = logging.getLogger(__name__)