feat(chat): add chat room management functionality

- Created new chat schema in the database.
- Implemented chat room model with necessary fields (title, ownerId, roomTypeId, etc.).
- Added room type model and rights model for chat functionality.
- Developed API endpoints for managing chat rooms, including create, edit, and delete operations.
- Integrated chat room management into the admin interface with a dedicated view and dialog for room creation/editing.
- Added internationalization support for chat room management UI.
- Implemented autocomplete for victim selection in underground activities.
- Enhanced the underground view with new activity types and political target selection.

backend/models/chat/user.js

@@ -0,0 +1,41 @@
+import { DataTypes } from 'sequelize';
+import { sequelize } from '../../utils/sequelize.js';
+
+const ChatUser = sequelize.define('ChatUser', {
+    id: {
+        type: DataTypes.INTEGER,
+        primaryKey: true,
+        autoIncrement: true,
+    },
+    falukant_user_id: {
+        type: DataTypes.INTEGER,
+        allowNull: false,
+        comment: 'Verknüpfung zu community.falukant_user',
+    },
+    display_name: {
+        type: DataTypes.STRING(64),
+        allowNull: false,
+    },
+    color: {
+        type: DataTypes.STRING(16), // z.B. Hex-Code
+        allowNull: false,
+        defaultValue: '#000000',
+    },
+    show_gender: {
+        type: DataTypes.BOOLEAN,
+        allowNull: false,
+        defaultValue: true,
+    },
+    show_age: {
+        type: DataTypes.BOOLEAN,
+        allowNull: false,
+        defaultValue: true,
+    },
+}, {
+    schema: 'chat',
+    tableName: 'user',
+    timestamps: true,
+    underscored: true,
+});
+
+export default ChatUser;