feat: initialisation du projet Olhar-API en Clean Architecture

- Spring Boot 3.4.1 + Gradle Kotlin DSL, Java 21
- Clean Architecture (domain / application / infrastructure / interfaces)
- Spring Security stateless avec JWT (JJWT 0.12.6)
- Flyway + PostgreSQL (migration V1 table users)
- SpringDoc OpenAPI / Swagger UI avec auth Bearer
- Testcontainers pour les tests d'intégration
- Use cases Register et Authenticate (endpoints POST /api/v1/auth/register et /login)
- GlobalExceptionHandler avec ProblemDetail (RFC 9457)
- docker-compose.yml pour Postgres local

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

build.gradle.kts

@@ -0,0 +1,69 @@
+import org.springframework.boot.gradle.tasks.bundling.BootJar
+
+plugins {
+    java
+    id("org.springframework.boot") version "3.4.1"
+    id("io.spring.dependency-management") version "1.1.7"
+}
+
+group = "com.olhar"
+version = "0.0.1-SNAPSHOT"
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+val testcontainersVersion = "1.20.4"
+
+dependencies {
+    // Spring Boot starters
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
+    implementation("org.springframework.boot:spring-boot-starter-security")
+    implementation("org.springframework.boot:spring-boot-starter-validation")
+
+    // Database
+    runtimeOnly("org.postgresql:postgresql")
+    implementation("org.flywaydb:flyway-core")
+    implementation("org.flywaydb:flyway-database-postgresql")
+
+    // OpenAPI / Swagger
+    implementation("org.springdoc:springdoc-openapi-starter-webmvc-ui:2.7.0")
+
+    // JWT
+    implementation("io.jsonwebtoken:jjwt-api:0.12.6")
+    runtimeOnly("io.jsonwebtoken:jjwt-impl:0.12.6")
+    runtimeOnly("io.jsonwebtoken:jjwt-jackson:0.12.6")
+
+    // Utils
+    compileOnly("org.projectlombok:lombok")
+    annotationProcessor("org.projectlombok:lombok")
+
+    // Test
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
+    testImplementation("org.springframework.security:spring-security-test")
+    testImplementation("org.testcontainers:junit-jupiter")
+    testImplementation("org.testcontainers:postgresql")
+    testCompileOnly("org.projectlombok:lombok")
+    testAnnotationProcessor("org.projectlombok:lombok")
+}
+
+dependencyManagement {
+    imports {
+        mavenBom("org.testcontainers:testcontainers-bom:${testcontainersVersion}")
+    }
+}
+
+tasks.withType<Test> {
+    useJUnitPlatform()
+}
+
+tasks.named<BootJar>("bootJar") {
+    archiveFileName.set("olhar-api.jar")
+}