market-research-reports: fix ledger validator crash on publication_date=not-stated

The sentinel "not-stated" is exactly 10 characters, so it satisfied the
len(publication) == 10 ISO-date guard and reached
date.fromisoformat("not-stated"), raising an uncaught ValueError instead of
the documented warning. SKILL.md instructs recording "not-stated" when the
publication date is unavailable, so this crashed on valid ledgers.

Check the sentinel before the retrieval/publication comparison, and add
regression tests for both the not-stated warning and the still-enforced
retrieval-precedes-publication error.

Fixes #219

skills/market-research-reports/SKILL.md

@@ -4,7 +4,7 @@ description: Build evidence-traceable market research reports and assumption-dri
 license: MIT
 compatibility: Python 3.11+ standard library for optional offline CLIs. The optional LaTeX template uses XeLaTeX or LuaLaTeX. Online research requires user-approved network access and source-specific terms; bundled scripts make no network, LLM, or image calls.
 metadata:
-  version: "1.1"
+  version: "1.2"
   skill-author: "K-Dense Inc."
 ---
 

skills/market-research-reports/scripts/validate_evidence_ledger.py

@@ -177,14 +177,14 @@ def validate_records(records: list[dict[str, Any]]) -> dict[str, Any]:
             retrieval = parse_iso_date(
                 record["retrieval_date"], f"{context}.retrieval_date"
             )
-            if len(publication) == 10 and date.fromisoformat(retrieval) < date.fromisoformat(
-                publication
-            ):
+            if publication == "not-stated":
+                warnings.append(f"{source_id}: publication date is not stated")
+            elif len(publication) == 10 and date.fromisoformat(
+                retrieval
+            ) < date.fromisoformat(publication):
                 raise ValidationError(
                     f"{context}.retrieval_date precedes publication_date"
                 )
-            if publication == "not-stated":
-                warnings.append(f"{source_id}: publication date is not stated")
 
             require_text(record["geography"], f"{context}.geography")
             currency = parse_currency(

tests/market-research-reports/test_scripts.py

@@ -59,6 +59,27 @@ class EvidenceLedgerTests(unittest.TestCase):
         self.assertFalse(report["valid"])
         self.assertTrue(any("duplicate" in error for error in report["errors"]))
 
+    def test_not_stated_publication_date_warns_without_crashing(self) -> None:
+        records = _load_records(ASSETS / "source_ledger_template.csv")
+        records[0]["publication_date"] = "not-stated"
+        report = validate_records(records)
+        self.assertTrue(report["valid"], report["errors"])
+        self.assertTrue(
+            any("publication date is not stated" in warning
+                for warning in report["warnings"])
+        )
+
+    def test_retrieval_before_publication_fails(self) -> None:
+        records = _load_records(ASSETS / "source_ledger_template.csv")
+        records[0]["publication_date"] = "2026-07-30"
+        records[0]["retrieval_date"] = "2026-07-01"
+        report = validate_records(records)
+        self.assertFalse(report["valid"])
+        self.assertTrue(
+            any("retrieval_date precedes publication_date" in error
+                for error in report["errors"])
+        )
+
 
 class MarketSizingTests(unittest.TestCase):
     def test_synthetic_sizing_reconciles_and_returns_scenarios(self) -> None: