Add translations for gold toast features in Korean

[Crazyyoungs]

What does this PR do?

Added Korean localization (koKR) for gold toast strips and toast scale settings.

How was it tested?

Tested in-game by applying the modified localization file to ensure strings display correctly without syntax errors.

Checklist

• New settings default OFF (no behavior change without opt-in)
• Zero cost while disabled: no events registered, no polling, no hooks doing work, no frames built
• Cheap while enabled: event-driven (no polling, no timer-based logic, no per-frame allocations)
• No writes onto Blizzard-owned frames (weak-table pattern used); HookScript/hooksecurefunc only, never SetScript on Blizzard frames
• Tested in-game, works on live retail; no load errors on the 12.1 PTR client