Add comprehensive documentation and unit tests

Documentation:
- Add detailed README files for all services (auth, character, database, launcher, packet, utils, world)
- Create API documentation for the database service with detailed endpoint specifications
- Document database schema and relationships
- Add service architecture overviews and configuration instructions

Unit Tests:
- Implement comprehensive test suite for database repositories (user, character, session)
- Add gRPC service tests for database interactions
- Create tests for packet service components (bufferpool, connection, packets)
- Add utility service tests (health check, logging, load balancer, redis cache, service discovery)
- Implement auth service user tests
- Add character service tests

Code Structure:
- Reorganize test files into a more consistent structure
- Create a dedicated tests crate for integration testing
- Add test helpers and mock implementations for easier testing

world-service/src/main.rs

@@ -1,7 +1,7 @@
 use dotenv::dotenv;
 use std::env;
-use utils::{health_check, logging};
 use utils::service_discovery::{get_kube_service_endpoints_by_dns, get_service_endpoints_by_dns};
+use utils::{health_check, logging};
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
@@ -12,7 +12,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Set the gRPC server address
     let addr = env::var("LISTEN_ADDR").unwrap_or_else(|_| "0.0.0.0".to_string());
     let port = env::var("SERVICE_PORT").unwrap_or_else(|_| "50054".to_string());
-    let db_url = format!("http://{}",get_kube_service_endpoints_by_dns("database-service","tcp","database-service").await?.get(0).unwrap());
+    let db_url = format!(
+        "http://{}",
+        get_kube_service_endpoints_by_dns("database-service", "tcp", "database-service")
+            .await?
+            .get(0)
+            .unwrap()
+    );
 
     // Register service with Consul
     health_check::start_health_check(addr.as_str()).await?;