fix: gross-based batch discard, direction-correct event logs, wire CSV logger

tests/test_do_batch.py

@@ -39,7 +39,8 @@ def test_net_counts_and_discard():
     assert should_discard_batch(0, 0) is True
     assert should_discard_batch(1, 0) is False
     assert should_discard_batch(0, 1) is False
-    assert should_discard_batch(-1, 0) is False
+    assert should_discard_batch(0, 7) is False
+    assert should_discard_batch(5, 0) is False
 
 
 def test_classify_unit_tokens():
@@ -265,7 +266,7 @@ def test_start_stop_auto_409(dash_client):
     assert res.status_code == 409
 
 
-def test_stop_discard_both_nets_zero(dash_client):
+def test_stop_discard_gross_zero(dash_client):
     client, mode_path, state_path, _ = dash_client
     office = {"Host": f"localhost:{cd_office_port()}"}
     client.post("/api/batch/mode", json={"mode": "manual"}, headers=office)
@@ -283,6 +284,24 @@ def test_stop_discard_both_nets_zero(dash_client):
     assert not state_path.exists()
 
 
+def test_stop_discards_zero_loading_with_unloading(dash_client):
+    client, mode_path, state_path, _ = dash_client
+    office = {"Host": f"localhost:{cd_office_port()}"}
+    client.post("/api/batch/mode", json={"mode": "manual"}, headers=office)
+    state_path.write_text(json.dumps({
+        "counting_date": "2026-09-24", "batch_number": 97,
+        "count": 0, "box_count": 0, "box_unloading": 0, "unloading": 7,
+        "start_time": "2026-09-24T00:00:00",
+        "model_mode": "C",
+    }))
+    res = client.post("/api/batch/stop", headers={"Host": "localhost:5000"})
+    body = res.get_json()
+    assert res.status_code == 200
+    assert body["discarded"] is True
+    assert body["net_sack"] == -7
+    assert not state_path.exists()
+
+
 def test_stop_keeps_box_only_batch(dash_client):
     client, mode_path, state_path, _ = dash_client
     office = {"Host": f"localhost:{cd_office_port()}"}