Fix global hotkey on Wayland

[voltage12]

Summary

Fix global hotkey registration in Linux Wayland sessions.

• Enable Electron's GlobalShortcutsPortal before app readiness.
• Upgrade Electron from 39.3.0 to 41.10.2 for Wayland Portal app-ID and preferred-trigger fixes.
• Enable CORS for the heynote-file protocol so Electron 41 can fetch stored images before copying them to the macOS clipboard.
• Surface failed hotkey registration in the settings error dialog.
• Replace the obsolete KDE KWin-script workaround with Portal documentation and migration guidance.
• Update the release workflow to Node 22, which Electron 41 requires.

Verification

• Added unit coverage for Portal activation, registration failures, and heynote-file protocol privileges.
• vue-tsc --noEmit
• npm run build
• Manual verification on KDE Plasma Wayland: global hotkey successfully toggles Heynote from another application; conflicting shortcuts report an error.

The existing KWin-script workaround remains compatible when used alone. Users should disable it before enabling the built-in global hotkey with the same shortcut.