Add Stripe notifications, messaging improvements, and code cleanup

Stripe Notifications:
- Add periodic task to check Stripe Connect accounts for requirements
- Create in-app notifications for business owners when action needed
- Add management command to setup Stripe periodic tasks
- Display Stripe notifications with credit card icon in notification bell
- Navigate to payments page when Stripe notification clicked

Messaging Improvements:
- Add "Everyone" option to broadcast message recipients
- Allow sending messages to yourself (remove self-exclusion)
- Fix broadcast message ID not returned after creation
- Add real-time websocket support for broadcast notifications
- Show toast when broadcast message received via websocket

UI Fixes:
- Remove "View all" button from notifications (no page exists)
- Add StripeNotificationBanner component for Connect alerts
- Connect useUserNotifications hook in TopBar for app-wide websocket

Code Cleanup:
- Remove legacy automations app and plugin system
- Remove safe_scripting module (moved to Activepieces)
- Add migration to remove plugin-related models
- Various test improvements and coverage additions

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/TopBar.tsx

@@ -8,6 +8,7 @@ import NotificationDropdown from './NotificationDropdown';
 import SandboxToggle from './SandboxToggle';
 import HelpButton from './HelpButton';
 import { useSandbox } from '../contexts/SandboxContext';
+import { useUserNotifications } from '../hooks/useUserNotifications';
 
 interface TopBarProps {
   user: User;
@@ -21,6 +22,9 @@ const TopBar: React.FC<TopBarProps> = ({ user, isDarkMode, toggleTheme, onMenuCl
   const { t } = useTranslation();
   const { isSandbox, sandboxEnabled, toggleSandbox, isToggling } = useSandbox();
 
+  // Connect to user notifications WebSocket for real-time updates
+  useUserNotifications({ enabled: !!user });
+
   return (
     <header className="flex items-center justify-between h-16 px-4 sm:px-8 bg-white dark:bg-gray-800 border-b border-gray-200 dark:border-gray-700 transition-colors duration-200 shrink-0">
       <div className="flex items-center gap-4">