strip: remove pattern/surge/chat alert monitoring + unused commands

- delete services/{patternChecker,patternStore,surgeChecker,chatAlertChecker,staffNotifications,staffChannel,notificationRegistry,notificationEnabled,staffPresence}.js
- remove /notification, /staffnotification, /tag, /priority
- /escalate: drop action param, always unclaim
- purge PATTERN_*, SURGE_*, CHAT_ALERT_*, STAFF_* env vars from config + .env.example
- drop StaffNotification model
- ~2500 LOC removed
- settings-site /internal/notifications/* endpoints gone (UI will 404 until trimmed)

models.js

@@ -864,14 +864,6 @@ mongoose.model('StaffSettings', new mongoose.Schema({
     updatedAt: { type: Date, default: Date.now }
 }));
 
-mongoose.model('StaffNotification', new mongoose.Schema({
-  userId: { type: String, required: true, unique: true },
-  guildId: String,
-  channelId: String,
-  cooldownHours: { type: Number, default: 1 },
-  updatedAt: { type: Date, default: Date.now }
-}));
-
 mongoose.model('StaffSignature', new mongoose.Schema({
   userId: { type: String, required: true, unique: true },
   guildId: { type: String, required: true },