test: cover the local scale branch and the decision policy

The shipped default scale had no test: make_session only builds matcher-backend
engines, so scale == "local" in _on_classified never ran in the suite - and
that is the branch that was wrong twice (the rank re-sort, and the early return
that made the text lane's fill-in job unreachable).

Adds LocalScaleEngine, which injects the lanes' evidence into the live path, and
two live tests: a text-only read still labels the track, and a text veto blocks a
local accept. Adds DecisionPolicyTests for the veto/fill-in boundary, including
the lane-order-vs-value case that the rank re-sort broke.

Both regressions were re-injected to confirm the tests fail for the intended
reason: restoring the early return fails the fill-in test, and re-sorting the
lane output by value fails the order test. Suite 251 -> 261.

recognization/code/test_engine.py

@@ -407,6 +407,72 @@ class LocalLaneTests(unittest.TestCase):
             engine.shutdown()
 
 
+class DecisionPolicyTests(unittest.TestCase):
+    """The two jobs the text lane does, and the boundary between them."""
+
+    def policy(self):
+        from identity_lanes import DecisionPolicy
+
+        return DecisionPolicy()
+
+    def test_local_answer_stands_when_the_text_agrees(self):
+        decision = self.policy().decide([("sku_a", 5.0)], [("sku_a", 0.9)])
+        self.assertEqual(decision["best_sku"], "sku_a")
+        self.assertEqual(decision["source"], "local")
+
+    def test_text_vetoes_a_local_answer_naming_another_row(self):
+        """The near-unknown case: real geometry, different words.
+
+        The veto blocks the local answer, and the text lane then names its own
+        row - the two jobs compose, so the result is the text's SKU, never the
+        vetoed local one.
+        """
+        decision = self.policy().decide([("sku_a", 5.0)], [("sku_b", 0.9)])
+        self.assertEqual(decision["best_sku"], "sku_b")
+        self.assertEqual(decision["source"], "text")
+
+    def test_text_mentioning_the_local_candidate_is_not_a_veto(self):
+        """A crop reading "マヨネーズ" scores every mayonnaise row.
+
+        The local candidate is usually one of them, so a veto needs the text to
+        *prefer* another row, not merely to mention it: here the text mentions
+        sku_b but explains sku_a better, so the local answer stands.
+        """
+        decision = self.policy().decide([("sku_a", 5.0)], [("sku_b", 0.4), ("sku_a", 0.45)])
+        self.assertEqual(decision["best_sku"], "sku_a")
+        self.assertEqual(decision["source"], "local")
+
+    def test_the_lanes_own_order_wins_over_the_value_order(self):
+        """Order and value are different quantities on the local lane.
+
+        The order comes from `rank_key` (inliers weighted by hue); the value is
+        the margin over the runner-up. Re-sorting by value names a different SKU
+        than the lane chose - here sku_b has the larger value but sku_a is the
+        lane's own first choice, and sku_a is what must be answered.
+        """
+        decision = self.policy().decide([("sku_a", 3.0), ("sku_b", 5.0)], [])
+        self.assertEqual(decision["best_sku"], "sku_a")
+
+    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")
+        self.assertEqual(decision["source"], "text")
+
+    def test_text_below_its_own_line_does_not_fill_in(self):
+        decision = self.policy().decide([], [("sku_b", 0.3)])
+        self.assertIsNone(decision["best_sku"])
+
+    def test_a_close_text_pair_does_not_fill_in(self):
+        """The margin gate: two rows the text explains equally must not name one."""
+        decision = self.policy().decide([], [("sku_b", 0.9), ("sku_c", 0.85)])
+        self.assertIsNone(decision["best_sku"])
+
+    def test_no_evidence_is_rejected(self):
+        decision = self.policy().decide([], [])
+        self.assertIsNone(decision["best_sku"])
+        self.assertEqual(decision["identity_level"], "rejected")
+
+
 class CatalogImageTests(unittest.TestCase):
     def test_catalog_image_path_is_resolved_through_inventory(self):
         engine, _, _, _ = make_engine()