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>

README.md

@@ -244,7 +244,7 @@ The reliable, universal payoff is **surgical context and speed**: CodeGraph coll
 | **Full-Text Search** | Find code by name instantly across your entire codebase, powered by FTS5 |
 | **Impact Analysis** | Trace callers, callees, and the full impact radius of any symbol before making changes |
 | **Always Fresh** | File watcher uses native OS events (FSEvents/inotify/ReadDirectoryChangesW) with debounced auto-sync — the graph stays current as you code, zero config |
-| **20+ Languages** | TypeScript, JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, C, C++, Objective-C, Metal, Swift, Kotlin, Scala, Dart, Lua, Luau, R, CFML, Svelte, Vue, Astro, Liquid, Pascal/Delphi |
+| **20+ Languages** | TypeScript, JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, C, C++, Objective-C, Metal, Swift, Kotlin, Scala, Dart, Lua, Luau, R, CFML, COBOL, Svelte, Vue, Astro, Liquid, Pascal/Delphi |
 | **Framework-aware Routes** | Recognizes web-framework routing files and links URL patterns to their handlers across 17 frameworks |
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@@ -716,6 +716,7 @@ is written):
 | R | `.R` `.r` | Full support (functions in every assignment form, S4/R5/R6 classes with methods, `library`/`require` imports, `source()` file references, call edges) |
 | Luau | `.luau` | Full support (everything in Lua, plus `type`/`export type` aliases, typed signatures, and Roblox instance-path `require`) |
 | CFML | `.cfc`, `.cfm`, `.cfs` | Full support (tag-based `<cfcomponent>`/`<cffunction>` and bare-script `component { ... }` styles, `extends`/`implements`, embedded `<cfscript>` delegation, call edges) |
+| COBOL | `.cbl`, `.cob`, `.cpy` | Full support (programs, sections/paragraphs with PERFORM/GO TO call edges, CALL 'literal' cross-program calls, COPY copybook imports — including standalone `.cpy` files — DATA DIVISION records/fields/88-levels, EXEC CICS LINK/XCTL and EXEC SQL INCLUDE targets; fixed and free format) |
 
 ## Measured cross-file coverage