MidnightNameplates 0.9.2 - Phase 9.2 Rule Manager Usability

NEW
- Add Current Target button for NPC rules.
- Recently Seen NPC list (up to 20 remembered, top 5 shown in manager).
- Recently Seen Spell list from actual observed nameplate casts.
- Click a recent NPC/spell to create its rule without typing.
- Rule color pickers:
  NPC: health color, frame color.
  Spell: cast color, cast border color.
- Rules page scroll canvas expanded.
- Existing add/search/rename/duplicate/delete/priority controls retained.
- Secret/restricted names are ignored rather than inspected.

TEST
1. Target an NPC, open Rules, press ADD CURRENT TARGET.
2. Verify the NPC appears in NPC Rules.
3. Fight several mobs and verify Recently Seen NPC entries.
4. Let enemies cast and verify Recently Seen Spell entries.
5. Click a recent entry to create a rule.
6. Test health/frame/cast/border color pickers.
7. Verify rules still persist after /reload.
8. Verify no Lua/taint/protected errors.
