Update classification logic for purchase orders

app/lib/utils/classifier.py

@@ -16,6 +16,8 @@ _KEYWORD_MAP: dict[str, dict[str, float]] = {
     "po": {
         "purchase order":       1.0,
         "purchase ord":         0.9,
+        "sales order":          1.0,
+        "sales ord":            0.9,
         "p.o.":                 0.6,
     },
     "invoice": {