feat: add hide-dock setting and fix about text handling (#3)

- Add "hideDockIcon" setting label and description to English locale,
  enabling users to remove VidBee from the macOS Dock and rely on the
  menu bar/tray icon.
- Apply dock visibility changes when settings change, when settings
  are loaded, and after settings are reset by calling
  applyDockVisibility from the settings service.
- Update About page to use about.description for share text and display
  content, replacing the removed tagline key usage.
- Remove unused "tagline" entries from multiple locale files (en, fr,
  it, pt, ja, zh) to keep translations in sync with UI text changes.

These changes add OS integration for hiding the dock icon and ensure UI
copy is consistent and correctly internationalized.

src/main/index.ts

@@ -10,6 +10,7 @@ import { downloadEngine } from './lib/download-engine'
 import { ytdlpManager } from './lib/ytdlp-manager'
 import { settingsManager } from './settings'
 import { createTray, destroyTray } from './tray'
+import { applyDockVisibility } from './utils/dock'
 
 // Initialize electron-log for main process
 log.initialize()
@@ -27,6 +28,7 @@ export function createWindow(): void {
     height: 800,
     show: false,
     titleBarStyle: 'hidden', // Hide title bar on macOS
+    trafficLightPosition: { x: 12.5, y: 10 },
     autoHideMenuBar: true,
     icon: appIcon, // Set application icon
     frame: false,
@@ -183,6 +185,8 @@ app.whenReady().then(async () => {
     log.error('Failed to initialize yt-dlp:', error)
   }
 
+  applyDockVisibility(settingsManager.get('hideDockIcon'))
+
   createWindow()
 
   initAutoUpdater()