refactor: enforce enum machine codes #18

Use owner enums for known codes; preserve wire values and unknown fallbacks.

Verified npm ci and verify: 379 tests, 5 lint checks, app and Storybook builds.

src/pages/accounts/ui/AccountsPage/components/AccountsPageError.view.tsx

@@ -5,6 +5,8 @@ import { StateView } from "@wealthledger/ui";
 import { useTranslation } from "react-i18next";
 import { Link } from "react-router";
 
+import { ApiErrorCode, isApiErrorCode } from "@/shared/api";
+
 type AccountsPageErrorProps = { code?: string; retry?: () => void };
 
 const AccountsPageError: FC<AccountsPageErrorProps> = (props) => {
@@ -15,7 +17,7 @@ const AccountsPageError: FC<AccountsPageErrorProps> = (props) => {
 			{t("accounts.openSettings")}
 		</Button>
 	);
-	if (code === "TBANK_NOT_CONNECTED")
+	if (isApiErrorCode(code, ApiErrorCode.TbankNotConnected))
 		return (
 			<StateView
 				action={settingsAction}
@@ -24,7 +26,7 @@ const AccountsPageError: FC<AccountsPageErrorProps> = (props) => {
 				title={t("accounts.notConnectedTitle")}
 			/>
 		);
-	if (code === "INVALID_TBANK_TOKEN")
+	if (isApiErrorCode(code, ApiErrorCode.InvalidTbankToken))
 		return (
 			<StateView
 				action={settingsAction}
@@ -33,7 +35,7 @@ const AccountsPageError: FC<AccountsPageErrorProps> = (props) => {
 				title={t("accounts.invalidTokenTitle")}
 			/>
 		);
-	if (code === "TBANK_UNAVAILABLE")
+	if (isApiErrorCode(code, ApiErrorCode.TbankUnavailable))
 		return (
 			<StateView
 				action={(