Initial project setup: CI, Docker & configs

Add project bootstrap for build, CI/CD, and local development. Introduces Maven Wrapper (mvnw, mvnw.cmd, .mvn/wrapper), multi-stage Dockerfile, docker-compose files (compose.yaml, docker-compose.dev.yml), .env, banner and README. Adds Gitea Actions workflow to build, test and push container images. Update application.yml (port -> 8090, virtual threads, API versioning, management/actuator/prometheus settings, Steam API config) and add application-dev.yml for local overrides. Extend pom.xml with caching, observability (actuator, micrometer/prometheus), testing/dev dependencies (testcontainers, devtools, additional spring test modules) to support CI and local testing.

readme.md

@@ -0,0 +1,82 @@
+# To Be Played (TBP) - Core Service
+
+This is the Core Service for the "To Be Played" project. It acts as the central modulith, handling all business logic in vertical micro-service ready slices.
+
+## 🚀 Tech Stack
+
+* **Language:** Java 25
+* **Framework:** Spring Boot 4.1.x
+* **Security:** Spring Security & JSON Web Tokens (JWT)
+* **Database:** PostgreSQL 17
+* **Migrations:** Flyway
+* **Observability:** Spring Boot Actuator & Micrometer (Prometheus)
+* **Build Tool:** Maven Wrapper (`mvnw`)
+* **CI/CD:** Gitea Actions (Forgejo)
+
+## 🏗️ Architecture (Clean Architecture)
+
+The project strictly follows a Domain-Driven / Clean Architecture (Ports & Adapters) approach to ensure high maintainability and testability. The codebase is divided into three main layers to prevent framework lock-in and keep business logic isolated.
+
+### Layer Breakdown
+
+1. **Controller / Web Layer (`controller`)**
+    * Contains REST endpoints, DTOs (`Request`/`Response` records), and Global Exception Handlers.
+    * Uses `ApiMapper` to map between DTOs and Domain Models.
+    * **Rule:** This layer delegates to the Service layer and never accesses persistence directly.
+
+2. **Domain / Core Layer (`model`, `service`, `exception`)**
+    * The heart of the application. Contains pure Java classes (Models) and Business Logic (Services).
+    * Throws specific business exceptions (e.g., `InvalidCredentialsException`).
+    * **Rule:** This layer has **no dependencies** on the Controller or Persistence layer. It defines interfaces that the persistence layer must implement.
+
+3. **Persistence Layer (`persistence`)**
+    * Handles database operations. Contains JPA Entities (`UserEntity`), Spring Data Repositories, and the `EntityMapper`.
+    * Implements the interfaces defined in the Domain layer.
+    * **Rule:** Entities never leak into the Controller layer.
+
+*Note: Future implementations will include ArchUnit tests to automatically enforce these architectural boundaries during the CI pipeline.*
+
+## ⚙️ Local Development
+
+Running the application locally is fully automated via Spring Boot's Docker Compose Support.
+
+### Prerequisites
+
+* Java 25 installed
+* Docker & Docker Compose running
+
+### How to start
+
+1. Simply run the application from your IDE (e.g., IntelliJ) via the `CoreServiceApplication.java` main class.
+2. Spring Boot will automatically detect the `compose.yaml` and spin up a local PostgreSQL container (`tbp_db_local`) on port `5432`.
+3. **Flyway** will automatically apply all database migrations located in `src/main/resources/db/migration`.
+4. The application will be available at `http://localhost:8090`.
+
+To stop the environment and clean the database volume (if needed):
+
+```bash
+docker compose down -v
+```
+
+## 🔐 API Versioning
+
+All API endpoints utilize Query Parameter Versioning to keep URLs clean and manageable.
+Example: GET /api/users/me?v=1
+
+## 🐳 CI/CD Pipeline
+
+The project uses Gitea Actions for Continuous Integration and Deployment.
+
+Quality Gate: Runs ./mvnw clean verify to ensure tests and builds pass.
+
+Docker Build: Packages the application using a multi-stage Dockerfile.
+
+Registry: Pushes the lightweight Alpine-based image to the private Gitea container registry (git.andreas-dahm.eu/lobo_corp/tbp-core-service:latest).
+
+## 📈 Observability
+
+Metrics and health checks are exposed out-of-the-box via Spring Boot Actuator:
+
+Health: http://localhost:8090/actuator/health
+
+Prometheus Metrics: http://localhost:8090/actuator/prometheus