MidnightNameplates 0.8.1 - Phase 8.1 Target Marker System

NEW
- Optional current-target marker. Disabled by default.
- Bundled original Midnight marker textures:
  * Midnight Target Arrow
  * Midnight Target Triangle
  * Midnight Target Chevron
  * Midnight Target Diamond
- Marker texture dropdown reads LibSharedMedia 'background' registrations, so compatible external SharedMedia textures can be selected.
- Position: Top, Bottom, Left, Right.
- Size, horizontal offset, position gap, alpha.
- Color modes: Midnight, Class, Custom, White.
- Optional pulse animation and speed.
- Live preview support.
- Marker is independent from target border/brackets, focus, mouseover, threat and execute warning.

TEST
1. /mnp -> Target -> enable Target Marker.
2. Try all four bundled Midnight marker textures.
3. Try TOP/BOTTOM/LEFT/RIGHT.
4. Change size, offsets, alpha and color modes live.
5. Enable pulse and change speed.
6. Target different mobs in a large pack: marker must appear ONLY on the current target.
7. Clear target: marker must disappear.
8. Verify existing target border/brackets can be independently disabled.
9. Verify casts, auras, threat, classification and execute warning remain stable.
10. Watch for Lua, taint and protected-action errors.
