feat: add TTR simulator and calculation engine, enhance member model with TTR adjustment constant

backend/models/Member.js

@@ -214,6 +214,13 @@ const Member = sequelize.define('Member', {
     allowNull: true,
     defaultValue: null
   },
+  ttrAdjustmentConstant: {
+    type: DataTypes.DECIMAL(6, 2),
+    allowNull: false,
+    defaultValue: 16,
+    field: 'ttr_adjustment_constant',
+    comment: 'Individuelle Änderungskonstante für TTR-Prognosen'
+  },
   qttr: {
     type: DataTypes.INTEGER,
     allowNull: true,

backend/models/User.js

@@ -34,6 +34,20 @@ const User = sequelize.define('User', {
     type: DataTypes.BOOLEAN,
     defaultValue: false,
   },
+  isHidden: {
+    type: DataTypes.BOOLEAN,
+    defaultValue: false,
+    allowNull: false,
+    field: 'is_hidden',
+    comment: 'System accounts hidden from member and user lists',
+  },
+  suppressEmails: {
+    type: DataTypes.BOOLEAN,
+    defaultValue: false,
+    allowNull: false,
+    field: 'suppress_emails',
+    comment: 'Do not deliver outgoing emails to this account',
+  },
   authCode: {
     type: DataTypes.STRING,
     allowNull: true