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.

src/main/resources/application-dev.yml

@@ -0,0 +1,20 @@
+# ─────────────────────────────────────────────
+# DEVELOPMENT CONFIGURATION
+# ─────────────────────────────────────────────
+# Overrides properties from application.yml when the 'dev' profile is active
+
+app:
+  cors:
+    # Local development: allow all origins to prevent CORS issues
+    allowed-origins: "*"
+
+# Optional: Make SQL logs visible for debugging
+spring:
+  jpa:
+    show-sql: true
+
+security:
+  jwt:
+    secret: "NzC9tQP1eTp496SxoVYslH1bqn81Tbfz74NjkFqdcVe7wayjcRN8IeZvJWd1s6NEWgwEXe9rdccvOn2HtJ4fdq"
+  steam:
+    api-key: "54EF220BF9A9BF849DB4E33FC4B0FDA3"