fix(scrape): add a client-side recency fallback for flagless portals

Step 1b.3's "scope to 14 days using the portal's recency flag" was
unsatisfiable on jobdanmark, which has no date filter or sort - the
agent either silently skipped the scoping or invented a flag, and the
CLIs now reject invented flags loudly. Every portal emits date, so the
instruction now filters client-side after the call, and stops
presenting --order (a sort) as interchangeable with a filter. Review
finding F32 (2026-08-19).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/test_scrape_provenance.py

@@ -78,5 +78,33 @@ class ScrapeProvenanceSpec(unittest.TestCase):
         )
 
 
+class TestRecencyFallback(unittest.TestCase):
+    """Step 1b.3 says to scope to the last 14 days via the portal's recency
+    flag - but not every portal has one (jobdanmark offers no date filter or
+    sort at all), which left the instruction unsatisfiable there: the agent
+    either silently skipped the scoping or invented a flag, and inventing a
+    flag is exactly what the UNKNOWN_FLAG rejection now errors on (review
+    finding F32, 2026-08-19). Every portal emits a `date` field, so
+    client-side filtering is always available as the fallback."""
+
+    def test_step1b_names_a_client_side_fallback_for_flagless_portals(self):
+        text = SKILL.read_text(encoding="utf-8")
+        self.assertIn(
+            "no recency flag",
+            text,
+            "Step 1b.3 must say what to do when a portal offers no recency flag",
+        )
+        self.assertIn(
+            "filter client-side",
+            text,
+            "the fallback is filtering results by their `date` field after the call",
+        )
+        self.assertIn(
+            "a sort is not a filter",
+            text,
+            "the instruction must stop presenting --order (a sort) as interchangeable with a filter",
+        )
+
+
 if __name__ == "__main__":
     unittest.main()