feat: paginate KIS balance inquiries

tests/integration/test_kis_submission_recovery_virtual.py

@@ -96,15 +96,17 @@ def _serve(state: _ExchangeState):
 
         def do_GET(self):
             if self.path.startswith("/uapi/domestic-stock/v1/trading/inquire-balance"):
-                self._reply(state.balance())
+                self._reply(state.balance(), tr_cont="E")
             else:
                 self._reply(state.daily_orders())
 
-        def _reply(self, payload):
+        def _reply(self, payload, *, tr_cont=None):
             raw = json.dumps(payload).encode()
             try:
                 self.send_response(200)
                 self.send_header("content-type", "application/json")
+                if tr_cont is not None:
+                    self.send_header("tr_cont", tr_cont)
                 self.send_header("content-length", str(len(raw)))
                 self.end_headers()
                 self.wfile.write(raw)