fix(cabinet): recover "Сервис недоступен" false-positive + top-up fixes

- health probe: tolerant timeout (12s) + retry before flagging the backend down. A
  hardcoded 5s probe racing auth bootstrap falsely showed ServiceUnavailableScreen on
  slow devices / cold mobile connections while the 30s API requests would have
  succeeded ("works on one device, not another on the same Wi-Fi"). The recovery poll
  self-reschedules with the tolerant timeout so slow devices auto-recover.
- TopUpAmount: fetch payment methods with a real query (fixes the infinite spinner on a
  cold cache / browser-back) and use canonical RUB for quick-amount chips so FX rounding
  can't reject a min-amount selection in non-RUB locales.
- settings UI: render secret values as a masked password input (pairs with the backend
  secret masking); leaving the field empty keeps the stored secret.
- deps: npm audit fix (18 -> 5 advisories).

Also bundles in-progress settings env-lock UI work.

src/components/admin/QuickToggles.tsx

@@ -13,7 +13,9 @@ interface QuickTogglesProps {
 export function QuickToggles({ settings, onUpdate, disabled, className }: QuickTogglesProps) {
   const { t } = useTranslation();
 
-  const booleanSettings = settings.filter((s) => s.type === 'bool' && !s.read_only);
+  const booleanSettings = settings.filter(
+    (s) => s.type === 'bool' && !s.read_only && !s.env_locked,
+  );
 
   if (booleanSettings.length === 0) {
     return null;

src/components/admin/SettingInput.tsx

@@ -40,7 +40,10 @@ export function SettingInput({ setting, onUpdate, disabled }: SettingInputProps)
   const inputRef = useRef<HTMLInputElement>(null);
 
   const currentValue = String(setting.current ?? '');
-  const needsTextarea = isLongValue(currentValue) || isListOrJsonKey(setting.key);
+  // Secrets are always edited via the single-line (password) input — never a textarea — and
+  // never pre-filled with the masked value, so leaving the field empty means "keep current".
+  const needsTextarea =
+    !setting.is_secret && (isLongValue(currentValue) || isListOrJsonKey(setting.key));
 
   // Auto-resize textarea
   useEffect(() => {
@@ -51,11 +54,19 @@ export function SettingInput({ setting, onUpdate, disabled }: SettingInputProps)
   }, [value, isEditing]);
 
   const handleStart = () => {
-    setValue(currentValue);
+    // For secrets, start from an empty field (the displayed value is just the mask) so the
+    // admin types a brand-new value; leaving it empty is treated as "no change".
+    setValue(setting.is_secret ? '' : currentValue);
     setIsEditing(true);
   };
 
   const handleSave = () => {
+    // Empty secret field = the admin opened edit but didn't change anything → keep the stored
+    // secret instead of overwriting it with an empty value.
+    if (setting.is_secret && value === '') {
+      handleCancel();
+      return;
+    }
     onUpdate(value);
     setIsEditing(false);
   };
@@ -128,7 +139,14 @@ export function SettingInput({ setting, onUpdate, disabled }: SettingInputProps)
       <div className="flex items-center gap-2">
         <input
           ref={inputRef}
-          type={setting.type === 'int' || setting.type === 'float' ? 'number' : 'text'}
+          type={
+            setting.is_secret
+              ? 'password'
+              : setting.type === 'int' || setting.type === 'float'
+                ? 'number'
+                : 'text'
+          }
+          autoComplete={setting.is_secret ? 'new-password' : undefined}
           value={value}
           onChange={(e) => setValue(e.target.value)}
           onKeyDown={(e) => {

src/components/admin/SettingRow.tsx

@@ -30,6 +30,10 @@ export function SettingRow({
   const displayName = t(`admin.settings.settingNames.${formattedKey}`, formattedKey);
   const description = setting.hint?.description ? stripHtml(setting.hint.description) : null;
 
+  // env-locked keys behave like read-only here: the .env value shadows the DB,
+  // so editing would be silently discarded by the bot. Show the value, no input.
+  const locked = setting.read_only || setting.env_locked;
+
   // Check if this is a long/complex value
   const isLongValue = (() => {
     const val = String(setting.current ?? '');
@@ -65,6 +69,15 @@ export function SettingRow({
                 {t('admin.settings.readOnly')}
               </span>
             )}
+            {setting.env_locked && !setting.read_only && (
+              <span
+                className="flex items-center gap-1 rounded-full bg-dark-600/50 px-2 py-0.5 text-xs font-medium text-dark-400"
+                title={t('admin.settings.envLockedHint')}
+              >
+                <LockIcon />
+                {t('admin.settings.envLocked')}
+              </span>
+            )}
           </div>
           {description && (
             <p className="mt-1.5 text-sm leading-relaxed text-dark-400">{description}</p>
@@ -100,10 +113,17 @@ export function SettingRow({
       <div
         className={`${isLongValue ? '' : 'flex items-center justify-between gap-3'} border-t border-dark-700/30 pt-3`}
       >
-        {setting.read_only ? (
-          // Read-only display
-          <div className="flex items-center gap-2 rounded-lg bg-dark-700/30 px-4 py-2.5 text-dark-300">
-            <span className="break-all font-mono text-sm">{String(setting.current ?? '-')}</span>
+        {locked ? (
+          // Read-only / env-locked display
+          <div className="flex flex-col gap-1.5">
+            <div className="flex items-center gap-2 rounded-lg bg-dark-700/30 px-4 py-2.5 text-dark-300">
+              <span className="break-all font-mono text-sm">{String(setting.current ?? '-')}</span>
+            </div>
+            {setting.env_locked && !setting.read_only && (
+              <p className="text-xs leading-relaxed text-dark-500">
+                {t('admin.settings.envLockedHint')}
+              </p>
+            )}
           </div>
         ) : setting.type === 'bool' ? (
           // Boolean toggle
@@ -158,7 +178,7 @@ export function SettingRow({
       </div>
 
       {/* Reset button for long values - shown below */}
-      {isLongValue && setting.has_override && !setting.read_only && setting.type !== 'bool' && (
+      {isLongValue && setting.has_override && !locked && setting.type !== 'bool' && (
         <div className="mt-3 flex justify-end">
           <button
             onClick={onReset}

src/components/admin/SettingsTableRow.tsx

@@ -37,6 +37,8 @@ export function SettingsTableRow({
   const isModified = setting.has_override;
   const isBool = setting.type === 'bool';
   const boolChecked = setting.current === true || setting.current === 'true';
+  // env-locked keys are pinned in .env and shadow the DB — show value, no input.
+  const locked = setting.read_only || setting.env_locked;
 
   const isLongValue = (() => {
     const val = String(setting.current ?? '');
@@ -84,14 +86,17 @@ export function SettingsTableRow({
               </span>
             )}
 
-            {setting.has_override && !setting.read_only && (
+            {setting.has_override && !locked && (
               <span className="rounded-full bg-sky-500/20 px-1.5 py-0.5 text-[10px] font-medium leading-none text-sky-400">
                 {t('admin.settings.badgeDb')}
               </span>
             )}
 
-            {setting.read_only && (
-              <span className="flex items-center gap-0.5 rounded-full bg-warning-500/15 px-1.5 py-0.5 text-[10px] font-medium leading-none text-warning-400">
+            {setting.env_locked && (
+              <span
+                className="flex items-center gap-0.5 rounded-full bg-warning-500/15 px-1.5 py-0.5 text-[10px] font-medium leading-none text-warning-400"
+                title={t('admin.settings.envLockedHint')}
+              >
                 {t('admin.settings.badgeEnv')}
                 <LockIcon className="h-3 w-3" />
               </span>
@@ -116,7 +121,7 @@ export function SettingsTableRow({
             isLongValue ? 'w-full' : 'max-lg:self-end lg:flex-shrink-0',
           )}
         >
-          {setting.read_only ? (
+          {locked ? (
             <span className="max-w-[240px] truncate rounded bg-dark-700/30 px-3 py-1.5 font-mono text-xs text-dark-400">
               {isBool
                 ? boolChecked
@@ -138,7 +143,7 @@ export function SettingsTableRow({
           )}
 
           {/* Reset button -- hover-reveal when has_override */}
-          {isModified && !setting.read_only && (
+          {isModified && !locked && (
             <button
               onClick={onReset}
               disabled={isResetting}

src/components/blocking/ServiceUnavailableScreen.tsx

@@ -4,13 +4,12 @@ import { useQueryClient } from '@tanstack/react-query';
 import { useBlockingStore } from '../../store/blocking';
 import { useFocusTrap } from '../../hooks/useFocusTrap';
 import { pingBackend, hasEverReachedBackend } from '../../api/health';
+import { HEALTH } from '../../config/constants';
 import { CloudWarningIcon, RestartIcon } from '@/components/icons';
 import { Button } from '@/components/primitives';
 import { cn } from '@/lib/utils';
 import BlockingShell from './BlockingShell';
 
-const POLL_INTERVAL_MS = 5000;
-
 /**
  * Full-screen state shown when the backend is unreachable (transport-level
  * failure), replacing the blank loader the app used to get stuck on. Polls the
@@ -54,20 +53,24 @@ export default function ServiceUnavailableScreen() {
     }
   }, [recover]);
 
-  // Auto-recovery: probe immediately on mount, then every POLL_INTERVAL_MS.
+  // Auto-recovery: probe on mount, then re-schedule after each result resolves. Self-chaining
+  // (rather than a fixed setInterval) prevents the now-longer tolerant probe from overlapping
+  // with itself.
   useEffect(() => {
     let cancelled = false;
+    let timer: ReturnType<typeof setTimeout> | undefined;
     const tick = async () => {
       if (cancelled) return;
       if (await pingBackend()) {
         if (!cancelled) recover();
+        return;
       }
+      if (!cancelled) timer = setTimeout(tick, HEALTH.RECOVERY_POLL_INTERVAL_MS);
     };
     void tick();
-    const id = setInterval(tick, POLL_INTERVAL_MS);
     return () => {
       cancelled = true;
-      clearInterval(id);
+      if (timer) clearTimeout(timer);
     };
   }, [recover]);