feat(nameplates): class color friendly player names

[Caedis]

What does this PR do?

Opt-in toggle in friendly plate cog, default off. Name-only mode unaffected.

How was it tested?

Forever 1.60.1 (70009)
Enable class color name in nameplate settings
Profit

Screenshots

Preview:

2026-09-27.00-28-17.mp4

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 on live; no version gates or pre-Midnight APIs added