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>

.claude/skills/agent-eval/corpus.json

@@ -421,7 +421,30 @@
       "repo": "https://github.com/tidyverse/ggplot2",
       "size": "Large",
       "files": "~1150",
-      "question": "When a ggplot object is printed, how does the plot actually get built and drawn \u2014 trace the path from print/plot to where geoms render. Name the key functions in order."
+      "question": "When a ggplot object is printed, how does the plot actually get built and drawn — trace the path from print/plot to where geoms render. Name the key functions in order."
+    }
+  ],
+  "COBOL": [
+    {
+      "name": "cics-genapp",
+      "repo": "https://github.com/cicsdev/cics-genapp",
+      "size": "Small",
+      "files": "~60",
+      "question": "When a new insurance policy is added through the LGTESTP1 CICS test harness, which programs handle the request on the way to the DB2 insert? Trace the path and name the programs in order."
+    },
+    {
+      "name": "carddemo",
+      "repo": "https://github.com/aws-samples/aws-mainframe-modernization-carddemo",
+      "size": "Medium",
+      "files": "~75",
+      "question": "How does the online bill-payment flow work — from the COBIL00C screen program to the transaction record being written? Name the paragraphs performed in order and the copybooks that define the records involved."
+    },
+    {
+      "name": "CobolCraft",
+      "repo": "https://github.com/meyfa/CobolCraft",
+      "size": "Medium",
+      "files": "~270",
+      "question": "How does an incoming player chat message travel from packet handling to being broadcast to the other connected players? Name the programs on the path in order."
     }
   ]
-}
+}