feat(auth): add optional authentication guard and extend AuthModule providers

Introduce `OptionalAuthGuard` to allow conditional authentication for routes. Update `AuthModule` to include `AuthGuard`, `OptionalAuthGuard`, and `RolesGuard` in providers and exports for broader reuse.

feat(app): integrate `AdminModule` into app module

Add `AdminModule` to the app's main module to enable administration functionalities.

feat(users): enhance user profiles with bio and avatar fields

Extend `UpdateUserDto` to include optional `bio` and `avatarUrl` fields for better user customization.

feat(categories): add functionality to count all categories

Implement `countAll` method in `CategoriesRepository` to fetch the total number of categories using raw SQL counting.

backend/src/auth/auth.module.ts

@@ -5,6 +5,9 @@ import { SessionsModule } from "../sessions/sessions.module";
 import { UsersModule } from "../users/users.module";
 import { AuthController } from "./auth.controller";
 import { AuthService } from "./auth.service";
+import { AuthGuard } from "./guards/auth.guard";
+import { OptionalAuthGuard } from "./guards/optional-auth.guard";
+import { RolesGuard } from "./guards/roles.guard";
 import { RbacService } from "./rbac.service";
 import { RbacRepository } from "./repositories/rbac.repository";
 
@@ -16,7 +19,21 @@ import { RbacRepository } from "./repositories/rbac.repository";
 		DatabaseModule,
 	],
 	controllers: [AuthController],
-	providers: [AuthService, RbacService, RbacRepository],
-	exports: [AuthService, RbacService, RbacRepository],
+	providers: [
+		AuthService,
+		RbacService,
+		RbacRepository,
+		AuthGuard,
+		OptionalAuthGuard,
+		RolesGuard,
+	],
+	exports: [
+		AuthService,
+		RbacService,
+		RbacRepository,
+		AuthGuard,
+		OptionalAuthGuard,
+		RolesGuard,
+	],
 })
 export class AuthModule {}