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

AGENTS.md

@@ -38,8 +38,8 @@ Indonesian (`karung`=sack, `truk`=truck); YOLO class names are English
   default seed `batch.default_mode: auto`).
   **Port split:** `mode` / `model_mode` / `require_plate` / `require_do` POSTs →
   office `:5721` only (403 on `:5000`); **`ocr_engine` office-only too**
-  (default `rapid`). Discard batch only if **both** `net_sack==0` and
-  `net_box==0`. DO helpers: `src/do_batch.py`, OCR: `src/do_ocr.py`;
+  (default `rapid`). Discard batch only if both **gross** `count==0` and
+  `box_loading==0` (nets kept in DB/API). DO helpers: `src/do_batch.py`, OCR: `src/do_ocr.py`;
   ERD: `ERD.md` (repo root).
 - **Counting filters by class name, not ID**: `SackDetector`/`BoxDetector`/
   `TruckDetector` filter via `BaseDetector(class_filter)` (`src/detection.py`);