Implement permission management and enhance user interface for permissions in the application

Add new permission routes and integrate permission checks across various existing routes to ensure proper access control. Update the UserClub model to include role and permissions fields, allowing for more granular user access management. Enhance the frontend by introducing a user dropdown menu for managing permissions and displaying relevant options based on user roles. Improve the overall user experience by implementing permission-based visibility for navigation links and actions throughout the application.

backend/models/UserClub.js

@@ -6,6 +6,7 @@ import Club from './Club.js';
 const UserClub = sequelize.define('UserClub', {
   userId: {
     type: DataTypes.INTEGER,
+    primaryKey: true,
     references: {
       model: User,
       key: 'id',
@@ -13,6 +14,7 @@ const UserClub = sequelize.define('UserClub', {
   },
   clubId: {
     type: DataTypes.INTEGER,
+    primaryKey: true,
     references: {
       model: Club,
       key: 'id',
@@ -22,6 +24,23 @@ const UserClub = sequelize.define('UserClub', {
     type: DataTypes.BOOLEAN,
     defaultValue: false,
   },
+  role: {
+    type: DataTypes.STRING(50),
+    defaultValue: 'member',
+    allowNull: false,
+    comment: 'User role: admin, trainer, team_manager, member'
+  },
+  permissions: {
+    type: DataTypes.JSON,
+    allowNull: true,
+    comment: 'Specific permissions: {diary: {read: true, write: true}, members: {...}, ...}'
+  },
+  isOwner: {
+    type: DataTypes.BOOLEAN,
+    defaultValue: false,
+    allowNull: false,
+    comment: 'True if user created the club'
+  }
 }, {
   underscored: true,
   tableName: 'user_club',