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/extraction/grammars.ts

@@ -42,6 +42,7 @@ const WASM_GRAMMAR_FILES: Record<GrammarLanguage, string> = {
   cfml: 'tree-sitter-cfml.wasm',
   cfscript: 'tree-sitter-cfscript.wasm',
   cfquery: 'tree-sitter-cfquery.wasm',
+  cobol: 'tree-sitter-cobol.wasm',
 };
 
 /**
@@ -123,6 +124,13 @@ export const EXTENSION_MAP: Record<string, Language> = {
   // XML: file-level tracking; the MyBatis extractor matches `<mapper namespace="...">`
   // shape and emits SQL-statement nodes (other XML returns empty).
   '.xml': 'xml',
+  // COBOL: programs (.cbl/.cob) and copybooks (.cpy). Vendored grammar
+  // (patched yutaro-sakamoto/tree-sitter-cobol) handles fixed-format column
+  // rules, EXEC CICS/SQL blocks, and standalone copybook fragments.
+  '.cbl': 'cobol',
+  '.cob': 'cobol',
+  '.cobol': 'cobol',
+  '.cpy': 'cobol',
   // Spring config: `application.properties` / `application-*.properties`. Same
   // shape as the `.yml` variants — the YAML/properties extractor emits one node
   // per leaf key, and the Spring resolver links `@Value("${k}")` references.
@@ -241,7 +249,7 @@ export async function loadGrammarsForLanguages(languages: Language[]): Promise<v
       // `class Foo(...)` as an ERROR that swallows the whole class (#237); we
       // vendor the upstream ABI-15 tree-sitter-c-sharp 0.23.5 wasm, which parses
       // primary constructors natively.
-      const wasmPath = (lang === 'pascal' || lang === 'scala' || lang === 'lua' || lang === 'luau' || lang === 'csharp' || lang === 'r' || lang === 'cfml' || lang === 'cfscript' || lang === 'cfquery')
+      const wasmPath = (lang === 'pascal' || lang === 'scala' || lang === 'lua' || lang === 'luau' || lang === 'csharp' || lang === 'r' || lang === 'cfml' || lang === 'cfscript' || lang === 'cfquery' || lang === 'cobol')
         ? path.join(__dirname, 'wasm', wasmFile)
         : require.resolve(`tree-sitter-wasms/out/${wasmFile}`);
       const language = await WasmLanguage.load(wasmPath);
@@ -459,6 +467,7 @@ export function getLanguageDisplayName(language: Language): string {
     cfml: 'CFML',
     cfscript: 'CFScript',
     cfquery: 'CFQuery (SQL)',
+    cobol: 'COBOL',
     unknown: 'Unknown',
   };
   return names[language] || language;