Implement rate limiting and enhance authentication flow

- Added rate limiting configuration for authentication endpoints, allowing customizable request limits via environment variables.
- Updated authentication flow to utilize HttpRequest for cookie management, ensuring secure handling of refresh tokens.
- Introduced a new endpoint to retrieve user subscription details.
- Enhanced the handling of Telegram bot token validation to prevent errors with empty tokens.
- Updated the application to serialize enums as strings for better documentation and compatibility with TypeScript.
- Improved test coverage for new features and adjustments in command handlers.

frontend/src/routes/instructions.tsx

@@ -0,0 +1,33 @@
+import { createFileRoute } from '@tanstack/react-router'
+import { useTranslation } from 'react-i18next'
+import { useRequireAuth } from '@/features/auth/guards'
+import { AppsCatalog } from '@/features/apps/AppsCatalog'
+
+export const Route = createFileRoute('/instructions')({ component: InstructionsPage })
+
+function InstructionsPage() {
+  const { t } = useTranslation()
+  const { isReady } = useRequireAuth()
+
+  if (!isReady) return null
+
+  return (
+    <div className="mx-auto flex w-full max-w-4xl flex-col gap-8 px-6 py-10">
+      <div>
+        <h1 className="text-2xl font-semibold tracking-tight">{t('instructions.title')}</h1>
+        <p className="mt-1 text-sm text-muted-foreground">{t('instructions.intro')}</p>
+      </div>
+
+      <ol className="flex flex-col gap-2 text-sm">
+        <li>1. {t('instructions.step1')}</li>
+        <li>2. {t('instructions.step2')}</li>
+        <li>3. {t('instructions.step3')}</li>
+      </ol>
+
+      <div>
+        <h2 className="mb-3 text-lg font-semibold tracking-tight">{t('instructions.appsTitle')}</h2>
+        <AppsCatalog />
+      </div>
+    </div>
+  )
+}