MidnightNameplates 0.11.1 - Dangerous Mob Marker + Important Cast Visual Alerts

NEW: DANGEROUS MOB MARKERS
- HIGH priority NPC rules can show a CHEVRON / DIAMOND marker.
- CRITICAL priority NPC rules can show a separate style.
- Marker anchor: TOP / BOTTOM / LEFT / RIGHT.
- Marker size and X/Y offsets.
- HIGH and CRITICAL colors are configurable.
- Marker artwork is generated from MidnightNameplates' own solid geometry; no Blizzard/third-party marker texture is used.

NEW: IMPORTANT CAST ALERTS
- HIGH/CRITICAL spell rules get a dedicated border around the Midnight cast bar.
- Separate HIGH/CRITICAL colors.
- Optional pulse for HIGH and CRITICAL casts.
- Configurable border thickness and pulse speed.
- Alert hides immediately when the cast stops.
- Uses only MidnightNameplates-owned solid textures and animation frames.

HOW TO TEST
1. Intelligence ON.
2. Create an NPC rule for a visible NPC with priority HIGH.
3. Marker should appear. Change to CRITICAL and verify style/color.
4. Change marker anchor/size/offset live.
5. Create a spell rule for a spell you can observe.
6. Set priority HIGH -> cast alert border/pulse.
7. Set priority CRITICAL -> stronger critical color/alert.
8. Cast ending/interruption -> alert disappears.
9. Disable Intelligence -> markers/alerts disappear.
10. Disable HIGH/CRITICAL marker toggles independently.
11. Existing target marker, auras, stacking, classification visibility and Blizzard suppression remain correct.
12. No Lua/taint/secret-value errors.
