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

server/swagger/doc.js

@@ -289,6 +289,11 @@ module.exports = {
                   events: { type: 'array', items: { type: 'string' }, example: ['Easy', 'Medium', 'Hard', 'Elite'] },
                 },
               },
+              zLevels: {
+                type: 'object',
+                description: 'Protocol 14 (PLAN_REDESIGNS §14.3.6, D374): whether ZLevels Remastered is loaded, and nothing more. Its levels are never read; its XP boosts are permissions an event lends through a Permissions until the event ends step.',
+                properties: { loaded: { type: 'boolean', example: true }, version: { type: 'string', example: '3.3.1' } },
+              },
             },
           },
           console: {