feat: заменить баннер отсутствия auth на модальное окно с согласием

Дизайн-баннер был легко закрываем и появлялся заново каждую сессию.
Теперь показывается блокирующее модальное окно без кнопки закрытия/
Escape/клика по фону — пройти дальше можно только явным подтверждением
'Я понимаю риски'. Согласие сохраняется в localStorage и не запрашивается повторно.

frontend/src/components/auth/LoginGate.tsx

@@ -1,13 +1,13 @@
 import { type ReactNode, useEffect, useState } from "react";
 import { Logo } from "@/components/layout/Logo";
 import { LoginScreen } from "@/components/auth/LoginScreen";
-import { NoAuthBanner } from "@/components/auth/NoAuthBanner";
+import { NoAuthModal } from "@/components/auth/NoAuthModal";
 import { checkCredentials, useAuthHeader } from "@/lib/auth";
 
 // "not-configured" and "authenticated" both render `children` the same way,
 // but they must stay distinct: only "not-configured" means this instance has
 // no AURUM_BASIC_AUTH_USER/PASSWORD at all (nginx never sent 401 to our
-// deliberately-wrong probe header), which is what triggers NoAuthBanner.
+// deliberately-wrong probe header), which is what triggers NoAuthModal.
 // Collapsing them back into one "not-required" state would make an
 // authenticated session with valid stored credentials show the "this
 // instance has no password" warning too.
@@ -56,7 +56,7 @@ export function LoginGate({ children }: { children: ReactNode }) {
 
   return (
     <>
-      {probe === "not-configured" && <NoAuthBanner />}
+      {probe === "not-configured" && <NoAuthModal />}
       {children}
     </>
   );

frontend/src/components/auth/NoAuthBanner.tsx

@@ -1,48 +0,0 @@
-import { useState } from "react";
-import { TriangleAlert, X } from "lucide-react";
-import { useTranslation } from "@/lib/i18n";
-
-const DISMISS_KEY = "aurum:noAuthBanner:dismissed";
-
-/** Shown by LoginGate for the entire session whenever this instance has no
- * AURUM_BASIC_AUTH_USER/PASSWORD configured (see frontend/docker-entrypoint.d/
- * 20-basic-auth.sh) — that state is otherwise only logged to the container's
- * stderr at startup, which most self-hosters never look at. Dismissal is
- * remembered only in sessionStorage, not localStorage, so the warning comes
- * back on the next visit instead of being silence-able forever. */
-export function NoAuthBanner() {
-  const { t } = useTranslation();
-  const [dismissed, setDismissed] = useState(() => {
-    try {
-      return sessionStorage.getItem(DISMISS_KEY) === "1";
-    } catch {
-      return false;
-    }
-  });
-
-  if (dismissed) return null;
-
-  function handleDismiss() {
-    setDismissed(true);
-    try {
-      sessionStorage.setItem(DISMISS_KEY, "1");
-    } catch {
-      // storage unavailable — banner just reappears on next render, harmless
-    }
-  }
-
-  return (
-    <div className="flex items-start gap-2.5 border-b border-danger/30 bg-danger/10 px-4 py-2.5 text-sm text-danger">
-      <TriangleAlert size={16} className="mt-0.5 shrink-0" />
-      <span className="flex-1">{t("auth.noAuthBanner")}</span>
-      <button
-        type="button"
-        onClick={handleDismiss}
-        aria-label={t("auth.noAuthBannerDismiss")}
-        className="shrink-0 rounded p-0.5 hover:bg-danger/20"
-      >
-        <X size={16} />
-      </button>
-    </div>
-  );
-}

frontend/src/components/auth/NoAuthModal.tsx

@@ -0,0 +1,53 @@
+import { useState } from "react";
+import { ShieldAlert } from "lucide-react";
+import { useTranslation } from "@/lib/i18n";
+
+const ACK_KEY = "aurum:noAuthAcknowledged";
+
+/** Shown by LoginGate once (ever, per browser) when this instance has no
+ * AURUM_BASIC_AUTH_USER/PASSWORD configured (see frontend/docker-entrypoint.d/
+ * 20-basic-auth.sh) — that state is otherwise only logged to the container's
+ * stderr at startup, which most self-hosters never look at. Unlike a normal
+ * Dialog, there is deliberately no backdrop-click, Escape, or X-button way
+ * out — the only way past it is the explicit "I understand the risk" button,
+ * whose click is what persists the acknowledgement. */
+export function NoAuthModal() {
+  const { t } = useTranslation();
+  const [acknowledged, setAcknowledged] = useState(() => {
+    try {
+      return localStorage.getItem(ACK_KEY) === "1";
+    } catch {
+      return false;
+    }
+  });
+
+  if (acknowledged) return null;
+
+  function handleAccept() {
+    setAcknowledged(true);
+    try {
+      localStorage.setItem(ACK_KEY, "1");
+    } catch {
+      // storage unavailable — modal just reappears next reload, harmless
+    }
+  }
+
+  return (
+    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 p-4">
+      <div className="w-full max-w-sm rounded-2xl border border-danger/30 bg-surface-1 p-6 text-center shadow-xl">
+        <div className="mx-auto mb-4 flex h-12 w-12 items-center justify-center rounded-full bg-danger/10 text-danger">
+          <ShieldAlert size={24} />
+        </div>
+        <h2 className="mb-2 text-base font-semibold text-text-primary">{t("auth.noAuthModalTitle")}</h2>
+        <p className="mb-6 text-sm text-text-secondary">{t("auth.noAuthModalBody")}</p>
+        <button
+          type="button"
+          onClick={handleAccept}
+          className="inline-flex h-10 w-full items-center justify-center rounded-lg bg-danger px-4 text-sm font-medium text-white transition-colors hover:opacity-90"
+        >
+          {t("auth.noAuthModalAccept")}
+        </button>
+      </div>
+    </div>
+  );
+}

frontend/src/lib/i18n.ts

@@ -54,8 +54,9 @@ const ru = {
   "auth.submitting": "Вход…",
   "auth.errorInvalidCredentials": "Неверный логин или пароль",
   "auth.errorUnreachable": "Не удалось подключиться к серверу. Проверьте соединение и попробуйте снова.",
-  "auth.noAuthBanner": "Этот экземпляр Aurum не защищён паролем — все данные доступны любому, кто до него достучится. Задайте AURUM_BASIC_AUTH_USER и AURUM_BASIC_AUTH_PASSWORD в .env, чтобы включить вход.",
-  "auth.noAuthBannerDismiss": "Понятно",
+  "auth.noAuthModalTitle": "Авторизация не настроена",
+  "auth.noAuthModalBody": "Этот экземпляр Aurum не защищён паролем — все данные доступны любому, кто до него достучится. Задайте AURUM_BASIC_AUTH_USER и AURUM_BASIC_AUTH_PASSWORD в .env, чтобы включить вход.",
+  "auth.noAuthModalAccept": "Я понимаю риски и хочу продолжить",
 
   "dashboard.errorLoading": "Не удалось загрузить данные дашборда. Проверьте, что backend запущен.",
   "dashboard.statRealIncomeLabel": "Реальный доход",
@@ -560,8 +561,9 @@ const en: Record<keyof typeof ru, string> = {
   "auth.submitting": "Signing in…",
   "auth.errorInvalidCredentials": "Incorrect username or password",
   "auth.errorUnreachable": "Couldn't reach the server. Check your connection and try again.",
-  "auth.noAuthBanner": "This Aurum instance has no password protection — all data is accessible to anyone who can reach it. Set AURUM_BASIC_AUTH_USER and AURUM_BASIC_AUTH_PASSWORD in .env to enable login.",
-  "auth.noAuthBannerDismiss": "Got it",
+  "auth.noAuthModalTitle": "Authentication not configured",
+  "auth.noAuthModalBody": "This Aurum instance has no password protection — all data is accessible to anyone who can reach it. Set AURUM_BASIC_AUTH_USER and AURUM_BASIC_AUTH_PASSWORD in .env to enable login.",
+  "auth.noAuthModalAccept": "I understand the risk and want to continue",
 
   "dashboard.errorLoading": "Failed to load dashboard data. Check that the backend is running.",
   "dashboard.statRealIncomeLabel": "Real income",