feat: implement VirtualEntity and DispatchLog models with corresponding tests and configuration

INSTRUCTIONS.md

@@ -45,7 +45,7 @@ employee is an AI-powered entity that:
 |------|-----------------------------------------|-------------|
 | 0    | Define project & write CLAUDE.md        | ✅ Done     |
 | 1    | Scaffold monorepo structure             | ✅ Done     |
-| 2    | Domain model (JPA entities)             | ⬜ Pending  |
+| 2    | Domain model (JPA entities)             | ✅ Done     |
 | 3    | Repositories                            | ⬜ Pending  |
 | 4    | Email Reader Service (IMAP)             | ⬜ Pending  |
 | 5    | Prompt Builder Service                  | ⬜ Pending  |
@@ -253,10 +253,16 @@ Tests to write (all should **fail** before implementation):
 > `VirtualEntity`. Make the tests in `EntityMappingTest` pass."
 
 **Done when:**
-- [ ] `EntityMappingTest.kt` exists with all 5 tests.
+- [x] `EntityMappingTest.kt` exists with all 5 tests.
-- [ ] Both entity files exist in `src/main/kotlin/com/condado/newsletter/model/`.
+- [x] Both entity files exist in `src/main/kotlin/com/condado/newsletter/model/`.
-- [ ] `./gradlew test` is green.
+- [x] `./gradlew test` is green.
-- [ ] Tables are auto-created by Hibernate on startup (`ddl-auto: create-drop` in dev).
+- [x] Tables are auto-created by Hibernate on startup (`ddl-auto: create-drop` in dev).
+
+**Key decisions made:**
+- Added `org.gradle.java.home=C:/Program Files/Java/jdk-21.0.10` to `gradle.properties` — the Kotlin DSL compiler embedded in Gradle 8.14.1 does not support JVM target 26, so the Gradle daemon must run under JDK 21.
+- Created `src/test/resources/application.yml` to override datasource and JPA settings for tests (H2 in-memory, `ddl-auto: create-drop`), and provide placeholder values for required env vars so tests run without Docker/real services.
+- `VirtualEntity` and `DispatchLog` use class-body `var` fields for `id` (`@GeneratedValue`) and `createdAt` (`@CreationTimestamp`) so Hibernate can set them; all other fields are constructor `val` properties.
+- `DispatchStatus` enum: `PENDING`, `SENT`, `FAILED`.
 
 ---
 

backend/gradle.properties

@@ -1,2 +1,3 @@
 org.gradle.jvmargs=-Xmx2g -XX:+HeapDumpOnOutOfMemoryError --enable-native-access=ALL-UNNAMED
+org.gradle.java.home=C:/Program Files/Java/jdk-21.0.10
 kotlin.code.style=official

backend/src/main/kotlin/com/condado/newsletter/model/DispatchLog.kt

@@ -0,0 +1,53 @@
+package com.condado.newsletter.model
+
+import jakarta.persistence.Column
+import jakarta.persistence.Entity
+import jakarta.persistence.EnumType
+import jakarta.persistence.Enumerated
+import jakarta.persistence.FetchType
+import jakarta.persistence.GeneratedValue
+import jakarta.persistence.GenerationType
+import jakarta.persistence.Id
+import jakarta.persistence.JoinColumn
+import jakarta.persistence.ManyToOne
+import jakarta.persistence.Table
+import java.time.LocalDateTime
+import java.util.UUID
+
+/**
+ * Records every AI generation and email send attempt for a given [VirtualEntity].
+ * Stores the prompt sent, the AI response, parsed subject/body, send status, and timestamp.
+ */
+@Entity
+@Table(name = "dispatch_logs")
+class DispatchLog(
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "entity_id", nullable = false)
+    val virtualEntity: VirtualEntity,
+
+    @Column(name = "prompt_sent", columnDefinition = "TEXT")
+    val promptSent: String? = null,
+
+    @Column(name = "ai_response", columnDefinition = "TEXT")
+    val aiResponse: String? = null,
+
+    @Column(name = "email_subject")
+    val emailSubject: String? = null,
+
+    @Column(name = "email_body", columnDefinition = "TEXT")
+    val emailBody: String? = null,
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    val status: DispatchStatus = DispatchStatus.PENDING,
+
+    @Column(name = "error_message")
+    val errorMessage: String? = null,
+
+    @Column(name = "dispatched_at", nullable = false)
+    val dispatchedAt: LocalDateTime = LocalDateTime.now()
+) {
+    @Id
+    @GeneratedValue(strategy = GenerationType.UUID)
+    var id: UUID? = null
+}

backend/src/main/kotlin/com/condado/newsletter/model/DispatchStatus.kt

@@ -0,0 +1,10 @@
+package com.condado.newsletter.model
+
+/**
+ * Represents the dispatch status of an AI-generated email send attempt.
+ */
+enum class DispatchStatus {
+    PENDING,
+    SENT,
+    FAILED
+}

backend/src/main/kotlin/com/condado/newsletter/model/VirtualEntity.kt

@@ -0,0 +1,49 @@
+package com.condado.newsletter.model
+
+import jakarta.persistence.Column
+import jakarta.persistence.Entity
+import jakarta.persistence.GeneratedValue
+import jakarta.persistence.GenerationType
+import jakarta.persistence.Id
+import jakarta.persistence.Table
+import org.hibernate.annotations.CreationTimestamp
+import java.time.LocalDateTime
+import java.util.UUID
+
+/**
+ * Represents a fictional employee of "Condado Abaixo da Média SA".
+ * Each entity has a scheduled time to send AI-generated emails, a personality description,
+ * and a context window for reading recent emails via IMAP.
+ */
+@Entity
+@Table(name = "virtual_entities")
+class VirtualEntity(
+    @Column(nullable = false)
+    val name: String,
+
+    @Column(unique = true, nullable = false)
+    val email: String,
+
+    @Column(name = "job_title", nullable = false)
+    val jobTitle: String,
+
+    @Column(columnDefinition = "TEXT")
+    val personality: String? = null,
+
+    @Column(name = "schedule_cron")
+    val scheduleCron: String? = null,
+
+    @Column(name = "context_window_days")
+    val contextWindowDays: Int = 3,
+
+    @Column(nullable = false)
+    val active: Boolean = true
+) {
+    @Id
+    @GeneratedValue(strategy = GenerationType.UUID)
+    var id: UUID? = null
+
+    @CreationTimestamp
+    @Column(name = "created_at", updatable = false)
+    var createdAt: LocalDateTime? = null
+}

backend/src/test/kotlin/com/condado/newsletter/model/EntityMappingTest.kt

@@ -0,0 +1,96 @@
+package com.condado.newsletter.model
+
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertThrows
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
+import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager
+import java.time.LocalDateTime
+
+@DataJpaTest
+class EntityMappingTest {
+
+    @Autowired
+    lateinit var entityManager: TestEntityManager
+
+    @Test
+    fun should_persistVirtualEntity_when_allFieldsProvided() {
+        val entity = VirtualEntity(
+            name = "João Silva",
+            email = "joao@condado.com",
+            jobTitle = "Chief Nonsense Officer",
+            personality = "Extremely formal but talks about cats",
+            scheduleCron = "0 9 * * 1",
+            contextWindowDays = 3
+        )
+
+        val saved = entityManager.persistAndFlush(entity)
+
+        assertThat(saved.id).isNotNull()
+        assertThat(saved.name).isEqualTo("João Silva")
+        assertThat(saved.email).isEqualTo("joao@condado.com")
+        assertThat(saved.jobTitle).isEqualTo("Chief Nonsense Officer")
+        assertThat(saved.personality).isEqualTo("Extremely formal but talks about cats")
+        assertThat(saved.scheduleCron).isEqualTo("0 9 * * 1")
+        assertThat(saved.contextWindowDays).isEqualTo(3)
+    }
+
+    @Test
+    fun should_enforceUniqueEmail_when_duplicateEmailInserted() {
+        val entity1 = VirtualEntity(name = "First", email = "dup@condado.com", jobTitle = "Dev")
+        val entity2 = VirtualEntity(name = "Second", email = "dup@condado.com", jobTitle = "Dev")
+
+        entityManager.persistAndFlush(entity1)
+
+        assertThrows<Exception> {
+            entityManager.persistAndFlush(entity2)
+        }
+    }
+
+    @Test
+    fun should_persistDispatchLog_when_linkedToVirtualEntity() {
+        val entity = VirtualEntity(name = "Maria Santos", email = "maria@condado.com", jobTitle = "COO")
+        val savedEntity = entityManager.persistAndFlush(entity)
+        entityManager.clear()
+
+        val log = DispatchLog(
+            virtualEntity = entityManager.find(VirtualEntity::class.java, savedEntity.id),
+            promptSent = "Test prompt content",
+            aiResponse = "SUBJECT: Test\nBODY:\nTest body",
+            emailSubject = "Test Subject",
+            emailBody = "Test body content",
+            status = DispatchStatus.SENT
+        )
+
+        val savedLog = entityManager.persistAndFlush(log)
+
+        assertThat(savedLog.id).isNotNull()
+        assertThat(savedLog.virtualEntity.id).isEqualTo(savedEntity.id)
+        assertThat(savedLog.status).isEqualTo(DispatchStatus.SENT)
+        assertThat(savedLog.promptSent).isEqualTo("Test prompt content")
+        assertThat(savedLog.emailSubject).isEqualTo("Test Subject")
+    }
+
+    @Test
+    fun should_setCreatedAtAutomatically_when_virtualEntitySaved() {
+        val before = LocalDateTime.now().minusSeconds(1)
+
+        val entity = VirtualEntity(name = "Auto Time", email = "time@condado.com", jobTitle = "Tester")
+        val saved = entityManager.persistAndFlush(entity)
+
+        val after = LocalDateTime.now().plusSeconds(1)
+
+        assertThat(saved.createdAt).isNotNull()
+        assertThat(saved.createdAt).isAfterOrEqualTo(before)
+        assertThat(saved.createdAt).isBeforeOrEqualTo(after)
+    }
+
+    @Test
+    fun should_defaultActiveToTrue_when_virtualEntityCreated() {
+        val entity = VirtualEntity(name = "Default Active", email = "active@condado.com", jobTitle = "CEO")
+        val saved = entityManager.persistAndFlush(entity)
+
+        assertThat(saved.active).isTrue()
+    }
+}

backend/src/test/resources/application.yml

@@ -0,0 +1,40 @@
+spring:
+  datasource:
+    url: jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
+    driver-class-name: org.h2.Driver
+    username: sa
+    password:
+  jpa:
+    hibernate:
+      ddl-auto: create-drop
+    show-sql: false
+    properties:
+      hibernate:
+        dialect: org.hibernate.dialect.H2Dialect
+  mail:
+    host: localhost
+    port: 25
+    username: test
+    password: test
+    properties:
+      mail:
+        smtp:
+          auth: false
+          starttls:
+            enable: false
+
+app:
+  password: testpassword
+  recipients: test@test.com
+  jwt:
+    secret: test-secret-key-for-testing-only-must-be-at-least-32-characters
+    expiration-ms: 86400000
+
+imap:
+  host: localhost
+  port: 993
+  inbox-folder: INBOX
+
+openai:
+  api-key: test-api-key
+  model: gpt-4o