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

auth-service/src/database_client.rs

@@ -1,56 +1,23 @@
-use crate::database::{user_service_client::UserServiceClient, GetUserByEmailRequest, GetUserByUsernameRequest, GetUserRequest, GetUserResponse};
+use crate::database::{
+    user_service_client::UserServiceClient, GetUserByEmailRequest, GetUserByUsernameRequest, GetUserRequest,
+    GetUserResponse,
+};
 use async_trait::async_trait;
-use chrono::{DateTime, Utc};
 use std::error::Error;
 use tonic::transport::Channel;
 
 #[async_trait]
 pub trait DatabaseClientTrait: Sized {
     async fn connect(endpoint: &str) -> Result<Self, Box<dyn std::error::Error>>;
-    async fn get_user_by_userid(
-        &mut self,
-        user_id: i32,
-    ) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
-    async fn get_user_by_username(
-        &mut self,
-        user_id: &str,
-    ) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
-    async fn get_user_by_email(
-        &mut self,
-        email: &str,
-    ) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
-    async fn store_password_reset(
-        &mut self,
-        email: &str,
-        reset_token: &str,
-        expires_at: DateTime<Utc>,
-    ) -> Result<(), Box<dyn std::error::Error>>;
-    async fn get_password_reset(
-        &self,
-        reset_token: &str,
-    ) -> Result<Option<PasswordReset>, Box<dyn std::error::Error>>;
-    async fn delete_password_reset(
-        &self,
-        reset_token: &str,
-    ) -> Result<(), Box<dyn std::error::Error>>;
-    async fn update_user_password(
-        &self,
-        email: &str,
-        hashed_password: &str,
-    ) -> Result<(), Box<dyn std::error::Error>>;
+    async fn get_user_by_userid(&mut self, user_id: i32) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
+    async fn get_user_by_username(&mut self, user_id: &str) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
+    async fn get_user_by_email(&mut self, email: &str) -> Result<GetUserResponse, Box<dyn std::error::Error>>;
 }
 #[derive(Clone)]
 pub struct DatabaseClient {
     client: UserServiceClient<Channel>,
 }
 
-#[derive(Debug)]
-pub struct PasswordReset {
-    pub email: String,
-    pub reset_token: String,
-    pub expires_at: DateTime<Utc>,
-}
-
 #[async_trait]
 impl DatabaseClientTrait for DatabaseClient {
     async fn connect(endpoint: &str) -> Result<Self, Box<dyn std::error::Error>> {
@@ -58,19 +25,13 @@ impl DatabaseClientTrait for DatabaseClient {
         Ok(Self { client })
     }
 
-    async fn get_user_by_userid(
-        &mut self,
-        user_id: i32,
-    ) -> Result<GetUserResponse, Box<dyn std::error::Error>> {
+    async fn get_user_by_userid(&mut self, user_id: i32) -> Result<GetUserResponse, Box<dyn std::error::Error>> {
         let request = tonic::Request::new(GetUserRequest { user_id });
         let response = self.client.get_user(request).await?;
         Ok(response.into_inner())
     }
 
-    async fn get_user_by_username(
-        &mut self,
-        username: &str,
-    ) -> Result<GetUserResponse, Box<dyn std::error::Error>> {
+    async fn get_user_by_username(&mut self, username: &str) -> Result<GetUserResponse, Box<dyn std::error::Error>> {
         let request = tonic::Request::new(GetUserByUsernameRequest {
             username: username.to_string(),
         });
@@ -85,35 +46,4 @@ impl DatabaseClientTrait for DatabaseClient {
         let response = self.client.get_user_by_email(request).await?;
         Ok(response.into_inner())
     }
-    
-    async fn store_password_reset(
-        &mut self,
-        _email: &str,
-        _reset_token: &str,
-        _expires_at: DateTime<Utc>,
-    ) -> Result<(), Box<dyn Error>> {
-        Ok(())
-    }
-
-    async fn get_password_reset(
-        &self,
-        _reset_token: &str,
-    ) -> Result<Option<PasswordReset>, Box<dyn std::error::Error>> {
-        todo!()
-    }
-
-    async fn delete_password_reset(
-        &self,
-        _reset_token: &str,
-    ) -> Result<(), Box<dyn std::error::Error>> {
-        Ok(())
-    }
-
-    async fn update_user_password(
-        &self,
-        _email: &str,
-        _hashed_password: &str,
-    ) -> Result<(), Box<dyn std::error::Error>> {
-        Ok(())
-    }
 }