Update zhCN.lua for 8.7.7

[Shiyan66666]

Updated Chinese translations for various UI elements and tooltips.

What does this PR do?

Update zhCN.lua for 8.7.7

How was it tested?

Screenshots

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