Do not auto-route POS through TMS proxy

pos_proxy.py

@@ -9,6 +9,14 @@ POS_PROXY_AUTH_QUERY_ENV = "POS_CASHIER_PROXY_AUTH_QUERY"
 POS_PROXY_TOKEN_HEADER = "X-POS-Proxy-Token"
 TMS_PROXY_URL_ENV = "TMS_CF_WORKER_URL"
 TMS_PROXY_TOKEN_ENV = "TMS_CF_WORKER_TOKEN"
+POS_PROXY_USE_TMS_ENV = "POS_CASHIER_USE_TMS_PROXY"
+
+
+def _env_flag(name, default=False):
+    raw = str(os.getenv(name, "")).strip().lower()
+    if not raw:
+        return default
+    return raw not in {"0", "false", "no", "off"}
 
 
 def _normalize_url(raw):
@@ -34,7 +42,12 @@ def _derive_pos_proxy_from_tms_proxy():
 def get_pos_proxy_base_url(proxy_url=None):
     if proxy_url is not None:
         return _normalize_url(proxy_url)
-    return _normalize_url(os.getenv(POS_PROXY_URL_ENV, "")) or _derive_pos_proxy_from_tms_proxy()
+    explicit_proxy_url = _normalize_url(os.getenv(POS_PROXY_URL_ENV, ""))
+    if explicit_proxy_url:
+        return explicit_proxy_url
+    if _env_flag(POS_PROXY_USE_TMS_ENV, False):
+        return _derive_pos_proxy_from_tms_proxy()
+    return ""
 
 
 def get_pos_origin(origin_url=None):