PourNotify v1.0.4

What's new\n\n- Replaces the PourNotify application identity with the owner-approved paper-airplane artwork across the executable, main window, taskbar, tray, and notification surfaces.\n- Adds an explicit --background mode for silent Windows login startup.\n- Adds a Start PourNotify automatically when I sign in setting that safely creates, updates, or removes one startup entry.\n- Preserves normal manual launch behavior, resident IPC forwarding, Codex notifications, Bark, sound, History, Diagnostics, quiet hours, duplicate handling, and existing configuration compatibility.\n\n## Validation\n\n- Ruff passed.\n- All 58 tests passed.\n- Clean PyInstaller Windows build passed.\n- Windows and macOS tag CI jobs passed.\n- Final Windows executable passed background startup, IPC notification, History, Diagnostics, desktop dispatch, and Bark HTTP 200 smoke validation.\n- Windows notification behavior and startup behavior were approved by the project owner.\n- Physical macOS runtime validation was not performed.\n\nOnly the Windows executable is published as a release asset.