Refraction DAG architect: multi-mode OPEN assigns the first mode to every file, so no program ever has an output (all JCL DDs DISP=SHR) #3204

Found by the #3120 differential. extract_lineage (gitgalaxy/tools/cobol_to_cobol/cobol_dag_architect.py) parses an OPEN statement with

re.finditer(r"OPEN\s+(INPUT|OUTPUT|I-O|EXTEND)\s+([^.]+)\.", safe_content)

That takes the first mode only and assigns it to every file up to the period. COBOL allows several modes in one OPEN:

           OPEN INPUT  TRANSACTION-FILE
                       CUSTOMER-FILE
                OUTPUT CUSTOMER-FILE-OUT
                       REPORT-FILE.

(zopeneditor SAM1.cbl:357). The result is inputs = {CUSTFILE, CUSTOUT, CUSTRPT, TRANFILE} and outputs = {}. The mode keyword OUTPUT is itself treated as a file token and ignored.

Effect

• Both corpora (zopeneditor, CBSA) report zero outputs for every program. So:
  • generate_zero_trust_jcl gives every DD DISP=SHR, never (NEW,CATLG,DELETE). The "zero-trust" JCL for SAM1 opens its two output files shared.
  • The DAG's topological sort has no producer edges, so the execution order is arbitrary.
• analyze_cobol_intent's SELECT regex is separate and fine here. The bug is only the OPEN-mode split.

Fix: tokenise the operand list and switch mode at each INPUT|OUTPUT|I-O|EXTEND keyword. Add the SAM1 shape as a test in tests/cobol_mainframe/test_cobol_dag_architect.py. The engine-side alternative (named OPEN-mode extraction) is filed separately.