fix: harden scheduler, permissions, and download safety

- Implement scheduler hydration barrier to prevent premature triggers
- Track scheduler exact runs using keys to avoid false stops
- Use 'System Events' for accurate macOS automation permissions
- Prevent system-sleep via proper idle assertions
- Ensure download pauses use channel acknowledgements (PauseWithAck)
- Require Firelink ownership before replacing files in add/conflict UI
- Retain partial download assets when removing entries without deletion
- Clear progress state in store when downloads complete or pause to reduce churn
- Handle empty/invalid queue selections gracefully

src/ipc.ts

@@ -40,13 +40,13 @@ type CommandMap = {
   set_concurrent_limit: { args: { limit: number }; result: void };
   set_global_speed_limit: { args: { limit: string | null }; result: void };
   request_automation_permission: { args: undefined; result: void };
+  check_automation_permission: { args: undefined; result: void };
   open_automation_settings: { args: undefined; result: void };
   get_free_space: { args: { path: string }; result: string };
   set_keychain_password: { args: { id: string; password: string }; result: void };
   get_keychain_password: { args: { id: string }; result: string };
   delete_keychain_password: { args: { id: string }; result: void };
   check_file_exists: { args: { path: string }; result: boolean };
-  delete_file: { args: { path: string }; result: void };
   toggle_tray_icon: { args: { show: boolean }; result: void };
   set_extension_pairing_token: { args: { token: string }; result: void };
   get_extension_server_port: { args: undefined; result: number | null };