feat(extraction): add COBOL language support (.cbl/.cob/.cpy) (#590, #648) (#1161)

Programs, sections/paragraphs (reconstructed extents over the grammar's
flat header stream), PERFORM/THRU/GO TO/CALL call edges, COPY copybook
imports incl. standalone .cpy fragments, DATA DIVISION records/fields/
88-levels with write-site impact references, and CICS flows: EXEC
LINK/XCTL program targets (literal + same-file VALUE deref), EXEC SQL
INCLUDE, and pseudo-conversational RETURN/START TRANSID hops resolved
to the owning program via a CICS framework resolver. Fixed and free
source format (free format via a scanner wide-mode sentinel).

Grammar: vendored wasm built from a patched yutaro-sakamoto/
tree-sitter-cobol (EXEC blocks as an external-scanner token, copybook
fragment entry point, single-quote continuation, COPY REPLACING
pseudo-text, NOT=, CALL GIVING, ENTRY, FREE, bitwise ops, abbreviated
relations, COBOL-2002 usages, and more). Patch + provenance + upstream
PR draft in docs/grammars/. Parse health: AWS CardDemo 43/44 native
(upstream: 9/31), 44/44 through preParse; copybooks 28/29; CobolCraft
free-format 17/17 (upstream: 0); NIST COBOL85 unchanged at 373/382.

Copybook members resolve to files like C includes (basename index,
name-matcher short-circuit so compiler-supplied members stay honestly
unresolved): CardDemo imports 5 -> 285. Impact proof: ACCT-CURR-BAL
(CVACT01Y copybook) surfaces its 4 writer programs cross-file.

Also: run-all.sh now neutralizes the ambient prompt-hook in both A/B
arms (CODEGRAPH_NO_PROMPT_HOOK=1); COBOL corpus entries for agent-eval.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/types.ts

@@ -98,6 +98,7 @@ export const LANGUAGES = [
   'cfml',
   'cfscript',
   'cfquery',
+  'cobol',
   'unknown',
 ] as const;