java.lang.IllegalArgumentException: Unknown entity

Bom dia pessoal, estou com dificuldade para configurar o projeto com o banco de dados PostgreSQL!

O link para o estado atual do meu projeto: https://1drv.ms/u/s!AmN8dMlWLIyttSgj3xqkd5xNH0yq

Ao submeter o formulário para salvar um produto (http://localhost:8080/alura/produtos/form), recebo o seguinte erro: HTTP Status 500 - Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown entity: br.com.gbd.alura.models.Produto.

Segue o código do model Produto:

package br.com.gbd.alura.models;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

/*
    Autor(es): José Carlos de Freitas
    Data: 05/03/2017 às 13:45:50
    Arquivo: Produto
 */

@Entity
public class Produto {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private int idProduto;

    private String titulo;
    private String descricao;
    private int paginas;

    public String getTitulo() {
        return titulo;
    }

    public void setTitulo(String titulo) {
        this.titulo = titulo;
    }

    public String getDescricao() {
        return descricao;
    }

    public void setDescricao(String descricao) {
        this.descricao = descricao;
    }

    public int getPaginas() {
        return paginas;
    }

    public void setPaginas(int paginas) {
        this.paginas = paginas;
    }

    @Override
    public String toString() {
        return "Produto [titulo=" + titulo + ", descricao=" + descricao + ", paginas=" + paginas + "]";
    }
}

Segue o ProdutoDAO

package br.com.gbd.alura.daos;

import br.com.gbd.alura.models.Produto;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

/*
    Autor(es): José Carlos de Freitas
    Data: 05/03/2017 às 13:52:26
    Arquivo: ProdutoDAO
 */

@Repository
@Transactional
public class ProdutoDAO {

    @PersistenceContext
    private EntityManager manager;

    public void gravar(Produto produto) {
        manager.persist(produto);
    }
}

Segue o ServletSpringMvc:

package br.com.gbd.alura.conf;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

/*
    Autor(es): José Carlos de Freitas
    Data: 05/03/2017 às 10:31:24
    Arquivo: ServletSpringMvc
 */

public class ServletSpringMvc extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return null;
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[] {AppWebConfiguration.class, JPAConfiguration.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] {"/"};
    }
}

Segue o JPAConfiguration

package br.com.gbd.alura.conf;

import java.util.Properties;
import javax.persistence.EntityManagerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.annotation.EnableTransactionManagement;

/*
    Autor(es): José Carlos de Freitas
    Data: 05/03/2017 às 13:56:52
    Arquivo: JPAConfiguration
*/

@EnableTransactionManagement
public class JPAConfiguration {

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean();
        JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();

        factoryBean.setJpaVendorAdapter(vendorAdapter);

        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setUsername("postgres");
        dataSource.setPassword("josecarlos");
        dataSource.setUrl("jdbc:postgresql://localhost:5432/alura");
        dataSource.setDriverClassName("org.postgresql.Driver");

        factoryBean.setDataSource(dataSource);

        Properties props = new Properties();
        props.setProperty("hibernate.dialect", "org.hibernate.dialect.PostgreSQLDialect");
        props.setProperty("hibernate.show_sql", "true");
        props.setProperty("hibernate.hbm2ddl.auto", "update");

        factoryBean.setJpaProperties(props);

        factoryBean.setPackagesToScan("br.com.casadocodigo.loja.models");

        return factoryBean;
    }

    @Bean
    public JpaTransactionManager transactionManager(EntityManagerFactory emf) {
        return new JpaTransactionManager(emf);
    }
}

Segue o ProdutoControler

package br.com.gbd.alura.controllers;

import br.com.gbd.alura.daos.ProdutoDAO;
import br.com.gbd.alura.models.Produto;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/*
    Autor(es): José Carlos de Freitas
    Data: 05/03/2017 às 13:39:58
    Arquivo: ProdutosController
 */
@Controller
public class ProdutosController {

    @Autowired
    private ProdutoDAO produtoDAO;

    @RequestMapping("/produtos/form")
    public String form() {
        return "produtos/form";
    }

    @RequestMapping("/produtos")
    public String gravar(Produto produto) {
        System.out.println(produto);
        produtoDAO.gravar(produto);

        return "produtos/ok";
    }
}

Segue o pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>br.com.gbd</groupId>
    <artifactId>alura</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>alura</name>

    <properties>
        <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--spring-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-servlet-api</artifactId>
            <version>8.5.11</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp.jstl</groupId>
            <artifactId>jstl-api</artifactId>
            <version>1.2</version>
            <exclusions>
                <exclusion>
                    <groupId>javax.servlet</groupId>
                    <artifactId>servlet-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>jstl-impl</artifactId>
            <version>1.2</version>
            <exclusions>
                <exclusion>
                    <groupId>javax.servlet</groupId>
                    <artifactId>servlet-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--log-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>jcl-over-slf4j</artifactId>
            <version>1.6.1</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.6.1</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.16</version>
            <scope>runtime</scope>
        </dependency>

        <!--jpa, hibernate e postgresql-->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>4.3.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.3.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.1-api</artifactId>
            <version>1.0.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>4.1.0.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.4.1212</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>casadocodigo</finalName>
        <plugins>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>