Position macOS traffic light buttons (trafficLightPosition) in the
BrowserWindow and add conditional left padding to the sidebar header
so the app logo and title clear the window management controls.
- Create shared platform detection utility (src/renderer/lib/platform.ts)
- Set trafficLightPosition { x: 16, y: 22 } on macOS in createMainWindow
- Apply pl-20 (80px) left padding to the sidebar header on macOS
- Consolidate navigator.platform check from keyboardShortcuts.ts
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
