MidnightNameplates 0.11.4.6
Safe Summon Source Ownership

CRITICAL STABILITY FIX
- Removed CVAR_UPDATE registration.
- Removed reactive CVar reassertion.
- Removed repeated 0 / 0.10 / 0.35 refresh chains.
- Removed summon CVar writes from generic SettingsChanged().
- Blizzard and Midnight no longer fight over Nameplate settings.

SOURCE WRITES NOW OCCUR ONLY ON CONTROLLED TRANSITIONS
- PLAYER_ENTERING_WORLD initialization
- Enable/disable summoned-unit controls
- Enable/disable an individual summon category
- Enable/disable Manage Blizzard minion nameplate sources

BLANK PLATE HANDLING
- When the last friendly summon category is disabled, Midnight restores the
  remembered friendly source state if configured.
- Same for enemy source.
- This prevents leaving a Blizzard source alive after Midnight has stopped
  rendering that summon category.

MANUAL BLIZZARD OPTIONS
- Manual changes in Blizzard Options are no longer immediately rewritten.
- No CVar feedback loop should occur.
- This specifically targets the severe lag/freeze seen in 11.4.5.

TEST
1. Reload.
2. Friendly Pet / Minion ON -> Bruufenn Midnight plate appears.
3. Turn Friendly Pet / Minion OFF in MNP.
   Expected: no blank health plate remains.
4. Turn it ON again -> Bruufenn returns.
5. Open Blizzard Options -> Nameplates -> Minions.
6. Toggle it manually OFF/ON.
   Expected: no severe lag spike, freeze, or CVar fighting.
7. Disable Manage Blizzard minion nameplate sources.
   Expected: original values restore once, then MNP stops touching them.
8. Re-enable management.
   Expected: one controlled update.
9. No Lua / taint / ADDON_ACTION_BLOCKED / secret-value errors.
