fix(auth,bank): guard switch-auth nav and surface banking retry

AuthForm disables the switch-auth Link while submit is pending so pointer
click and Enter can no longer leave the auth route and lose the draft/error
context. The form restores a true Link after the request settles.

CardsPage/CardPage distinguish cold vs cached banking failures:
- cold card/section errors expose accessible alert + retry
- cached failures keep the previous data and offer a section GET retry
- summary-only/history-only outages do not hide successful sections
- notFound still skips the retry CTA

Tests cover the pending link guard, cold/cached cards error with retry,
summary failure with retry, and the prerequisite card list recovery.

Closes #56, #57

src/features/auth/ui/AuthForm/AuthForm.tsx

@@ -1,4 +1,4 @@
-import type { FC } from "react";
+import type { FC, ReactNode } from "react";
 
 import { zodResolver } from "@hookform/resolvers/zod";
 import { Alert, Button, Fieldset, PasswordInput, Stack, TextInput } from "@mantine/core";
@@ -15,7 +15,7 @@ import {
 
 type AuthFormProps = {
 	onSubmit: (email: string, password: string) => Promise<void>;
-	register?: true;
+	register?: boolean;
 };
 
 const AuthForm: FC<AuthFormProps> = (props) => {
@@ -45,6 +45,24 @@ const AuthForm: FC<AuthFormProps> = (props) => {
 	});
 
 	const to = register ? "/login" : "/register";
+	const switchLabel = t(register ? "auth.haveAccount" : "auth.noAccount");
+
+	let switchLink: ReactNode;
+
+	if (isSubmitting) {
+		switchLink = (
+			<Button aria-disabled disabled variant="subtle">
+				{switchLabel}
+			</Button>
+		);
+	}
+	else {
+		switchLink = (
+			<Button component={Link} to={to} variant="subtle">
+				{switchLabel}
+			</Button>
+		);
+	}
 
 	return (
 		<FormProvider {...methods}>
@@ -77,9 +95,7 @@ const AuthForm: FC<AuthFormProps> = (props) => {
 							{t(register ? "auth.register" : "auth.login")}
 						</Button>
 
-						<Button component={Link} to={to} variant="subtle">
-							{t(register ? "auth.haveAccount" : "auth.noAccount")}
-						</Button>
+						{switchLink}
 					</Stack>
 				</Fieldset>
 			</form>