feat(rust): ZLevels Remastered on the servers page (PLAN_REDESIGNS §14.3.6)

Stage 7 of the §14.3 integration plan (D374): Server settings' plugin
line says whether ZLevels is loaded and that an event may lend its XP
boosts as permissions. The integrations schema gains zLevels; the
swagger fragment is regenerated. No leaderboard change, nothing stored.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

README.md

@@ -144,6 +144,11 @@ one now, kept when the run ends: an airdrop or a patrol helicopter can be sent t
   alone — and the run log says so. Refused where Guarded Crate or NpcSpawn is absent, where the event
   is not one the server has, or where the framework cannot run its console command
   (`docs/modules/rust/PLAN_REDESIGNS.md` §14.3.5).
+- **ZLevels Remastered** (nivex, 3.3.1). The servers page says whether it is loaded, and that is all:
+  its levels are never read, and the leaderboard has no column for them. Its XP boosts are its own
+  permissions (`zlevelsremastered.vip1`–`vip3`), so a *Double XP weekend* is a **Permissions until the event ends**
+  step, which takes effect at once and is taken back when the run ends
+  (`docs/modules/rust/PLAN_REDESIGNS.md` §14.3.6).
 
 News and event lines said in chat can wear one styled group's title and colours — the
 **announcement voice**, chosen in Admin → Rust servers. The line is said by the bridge plugin with no