Implement dark theme and comprehensive profile settings with working functionality

backend/src/modules/users/users.resolver.ts

@@ -36,4 +36,22 @@ export class UsersResolver {
   ) {
     return this.usersService.update(user.id, { bio, avatar });
   }
+
+  @Mutation(() => User)
+  @UseGuards(GqlAuthGuard)
+  updateProfile(
+    @CurrentUser() user: User,
+    @Args('bio') bio: string,
+  ) {
+    return this.usersService.update(user.id, { bio });
+  }
+
+  @Mutation(() => User)
+  @UseGuards(GqlAuthGuard)
+  updateOnlineStatus(
+    @CurrentUser() user: User,
+    @Args('isOnline') isOnline: boolean,
+  ) {
+    return this.usersService.updateOnlineStatus(user.id, isOnline);
+  }
 }

backend/src/modules/users/users.service.ts

@@ -55,10 +55,11 @@ export class UsersService {
     return this.findOne(id);
   }
 
-  async updateOnlineStatus(id: string, isOnline: boolean): Promise<void> {
+  async updateOnlineStatus(id: string, isOnline: boolean): Promise<User> {
     await this.usersRepository.update(id, {
       isOnline,
       lastSeen: isOnline ? undefined : new Date(),
     });
+    return this.findOne(id);
   }
 }