Allow manual payment tx submission during transient validation

frontend/components/account/__tests__/paymentSecurity.test.ts

@@ -94,6 +94,12 @@ export function runTests() {
       paymentFlowSource.includes("/validate"),
     "manual payment flow must validate tx hashes with the backend before submission",
   );
+  assert(
+    paymentFlowSource.includes("confirmRes.status === 503") &&
+      paymentFlowSource.includes('lowerRaw.includes("cannot connect payment rpc")') &&
+      paymentFlowSource.includes('lowerRaw.includes("payment rpc chain mismatch")'),
+    "manual payment confirm must treat transient payment RPC failures as pending after tx hash submission",
+  );
   assert(
     paymentFlowSource.includes("await waitForReceipt(txHashNorm, eth)") &&
       paymentFlowSource.indexOf("await waitForReceipt(txHashNorm, eth)") <

frontend/components/account/usePaymentFlow.ts

@@ -826,6 +826,9 @@ export function usePaymentFlow(params: UsePaymentFlowParams) {
         const lowerRaw = raw.toLowerCase();
         const maybePending =
           confirmRes.status === 408 ||
+          (confirmRes.status === 503 &&
+            (lowerRaw.includes("cannot connect payment rpc") ||
+              lowerRaw.includes("payment rpc chain mismatch"))) ||
           (confirmRes.status === 409 && (lowerRaw.includes("confirmations not enough") || lowerRaw.includes("tx indexed partially")));
         if (maybePending) {
           setPaymentInfo(`交易已提交: ${shortAddress(txHashNorm)}，等待链上确认中...`);