Adds system notifications for scheduler events: toasts appear in the bottom-right of the screen when a scheduled run starts, finishes (exited/killed), or errors. Notifications can be turned on or off from the toolbar and follow the app theme.

Changes

Config

• New option scheduler_notification_enabled in config.json with load_scheduler_notification_enabled() / save_scheduler_notification_enabled() in config.py.

New module: src/notifications.py

• show_notification(event_type, schedule_name, script_name, rule_type, next_run, palette, error_message=None) – shows a toast with preformatted strings (no schedule dicts or scheduler engine).
• update_notification_theme(palette) – updates the current toast when the user switches theme.
• Queue – multiple events show toasts one after another (4s each or until closed).
• Toast UI – rectangular window, object name notificationToast, bottom-right placement, topmost, 4s auto-close, close button with drawn X icon and "Close notification" tooltip. Styled via existing palette in theme.py.

GUI (gui.py)

• Top bar – New Notification button (Project | Terminal | Venv | Notification | Theme) with dropdown Scheduled: On / Off that toggles and persists the flag.
• Helpers – _format_next_run_for_notification() (time: on HH:MM dd/mm/yy, interval: in Xh Ym or seconds when < 1 min), _build_notification_payload() (uses format_rule_display() for rule text), _get_schedule_and_history_for_id() to resolve schedule from history.
• Trigger points (only when notifications are enabled):
  • Scheduled run start (after successful start in _execute_scheduled_run).
  • Scheduled run error (validate_trigger failure and exception in run_script_in_gitbash_captured).
  • Scheduled run exited (check_processes when process exits).
  • Scheduled run killed (manual Kill in _kill_script_row and when scheduler kills before next run in _execute_scheduled_run).
• Theme – _toggle_theme() calls update_notification_theme(self._palette) so toasts follow light/dark.

Theme (theme.py)

• QSS for #notificationToast, #notificationTitle, #notificationBody, #notificationError, and #notificationCloseBtn (red border/icon, hover state) using existing palette keys.

Behavior

• Scope: Only scheduler-triggered runs produce notifications; manual runs from Home do not.
• Content: Each toast shows schedule name, script name, rule (e.g. "Interval: 1min"), and next run (with seconds when under 1 minute). Error toasts include the error message.
• Dependencies: gui.py → notifications; notifications receive only strings and palette, no scheduler_engine or schedule dicts.