feat: add Van's real baseline lane and stop size tokens naming products

Two review findings, both confirmed by measurement.

1. The evaluator had no always-argmax lane, so every "vs Van" claim compared
   against the *gated* matcher, which is not Van's contract - the original demo
   answered every crop with its best-scoring SKU and had no accept line. The new
   'van' lane is that contract: same scores, no gate. Against it the local lane
   wins both axes at both resolutions (full 61%/77% vs 52%/29%; live 59%/95% vs
   57%/32%), but the live coverage margin is one facing, not seven, and the 95%
   figure is live-resolution only - at full resolution the same lane reads 77%
   with 11 false accepts and a hub alarm.

2. A crop reading only "400g" scored 0.667 on three SKUs, above TEXT_ACCEPT, so
   the text lane named a product from a size line. The fill-in job now requires
   two non-digit bigrams; the veto is unchanged, so "65%" still contradicts a
   local answer. The raw OCR read travels with the ranking through
   score_crop_lanes for that check.

Tests: 3 for the size gate (policy + live) and the van lane's own row. Removing
the gate fails all three. Suite 276 -> 280.

recognization/code/test_engine.py

@@ -453,6 +453,22 @@ class DecisionPolicyTests(unittest.TestCase):
         decision = self.policy().decide([("sku_a", 3.0), ("sku_b", 5.0)], [])
         self.assertEqual(decision["best_sku"], "sku_a")
 
+    def test_a_size_only_read_does_not_fill_in(self):
+        """Size and number tokens are not identity text."""
+        decision = self.policy().decide([], [("sku_b", 0.9)], text_read="400g")
+        self.assertIsNone(decision["best_sku"])
+
+    def test_a_size_only_read_still_vetoes(self):
+        """The veto keeps "65%" usable: the local lane supplied the evidence."""
+        decision = self.policy().decide(
+            [("sku_a", 5.0)], [("sku_b", 0.9)], text_read="65%"
+        )
+        self.assertIsNone(decision["best_sku"])
+
+    def test_a_named_read_with_a_size_still_fills_in(self):
+        decision = self.policy().decide([], [("sku_b", 0.9)], text_read="コクうま 65%")
+        self.assertEqual(decision["best_sku"], "sku_b")
+
     def test_text_fills_in_when_local_has_nothing(self):
         decision = self.policy().decide([], [("sku_b", 0.9)])
         self.assertEqual(decision["best_sku"], "sku_b")