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

packet-service/src/handlers/character.rs

@@ -7,16 +7,15 @@ use crate::enums::ItemType;
 use crate::packet::{send_packet, Packet, PacketPayload};
 use crate::packet_type::PacketType;
 use crate::packets::*;
+use std::collections::hash_map::DefaultHasher;
 use std::error::Error;
+use std::hash::{Hash, Hasher};
 use std::sync::Arc;
 use tokio::net::TcpStream;
 use tokio::sync::Mutex;
 use tonic::{Code, Status};
 use tracing::{debug, error, info, warn};
 use utils::null_string::NullTerminatedString;
-use std::hash::{Hash, Hasher};
-use std::collections::hash_map::DefaultHasher;
-
 
 fn string_to_u32(s: &str) -> u32 {
     let mut hasher = DefaultHasher::new();
@@ -80,20 +79,16 @@ pub(crate) async fn handle_char_list_req(
     let request = CliCharListReq::decode(packet.payload.as_slice());
     debug!("{:?}", request);
 
-    let mut user_id= "".to_string();
+    let mut user_id = "".to_string();
     let session_id;
     if let Some(mut state) = connection_service.get_connection(&connection_id) {
         user_id = state.user_id.expect("Missing user id in connection state");
-        session_id = state
-            .session_id
-            .expect("Missing session id in connection state");
+        session_id = state.session_id.expect("Missing session id in connection state");
     }
 
     // query the character service for the character list for this user
     let mut character_client = character_client.lock().await;
-    let character_list = character_client
-        .get_character_list(&user_id)
-        .await?;
+    let character_list = character_client.get_character_list(&user_id).await?;
     let mut characters = vec![];
     let mut character_id_list: Vec<u32> = Vec::new();
     for character in character_list.characters {
@@ -154,9 +149,7 @@ pub(crate) async fn handle_create_char_req(
     let session_id;
     if let Some(mut state) = connection_service.get_connection(&connection_id) {
         user_id = state.user_id.expect("Missing user id in connection state");
-        session_id = state
-            .session_id
-            .expect("Missing session id in connection state");
+        session_id = state.session_id.expect("Missing session id in connection state");
     }
 
     // send the data to the character service to create the character
@@ -181,10 +174,7 @@ pub(crate) async fn handle_create_char_req(
         _ => srv_create_char_reply::Result::Failed,
     };
 
-    let data = SrvCreateCharReply {
-        result,
-        platininum: 0,
-    };
+    let data = SrvCreateCharReply { result, platininum: 0 };
     let response_packet = Packet::new(PacketType::PakccCreateCharReply, &data)?;
     send_packet(stream, &response_packet).await?;
 
@@ -209,9 +199,7 @@ pub(crate) async fn handle_delete_char_req(
 
     if let Some(mut state) = connection_service.get_connection(&connection_id) {
         user_id = state.user_id.expect("Missing user id in connection state");
-        session_id = state
-            .session_id
-            .expect("Missing session id in connection state");
+        session_id = state.session_id.expect("Missing session id in connection state");
         character_id_list = state.character_list.expect("Missing character id list");
     }
 
@@ -256,10 +244,7 @@ pub(crate) async fn handle_select_char_req(
     let mut character_id_list: Vec<u32> = Vec::new();
     if let Some(mut state) = connection_service.get_connection_mut(&connection_id) {
         user_id = state.user_id.clone().expect("Missing user id in connection state");
-        character_id_list = state
-            .character_list
-            .clone()
-            .expect("Missing character id list");
+        character_id_list = state.character_list.clone().expect("Missing character id list");
         state.character_id = Some(request.char_id as i8);
     }
 
@@ -274,10 +259,7 @@ pub(crate) async fn handle_select_char_req(
 
     let mut character_client = character_client.lock().await;
     let character_data = character_client
-        .get_character(
-            &user_id.to_string(),
-            character_id_list[request.char_id as usize] as u8,
-        )
+        .get_character(&user_id.to_string(), character_id_list[request.char_id as usize] as u8)
         .await?;
 
     let character = character_data.character.unwrap_or_default();
@@ -332,8 +314,7 @@ pub(crate) async fn handle_select_char_req(
 
     let mut effect_list: [StatusEffect; (MAX_STATUS_EFFECTS as usize)] =
         core::array::from_fn(|i| StatusEffect::default());
-    let mut hotbar_list: [HotbarItem; (MAX_HOTBAR_ITEMS as usize)] =
-        core::array::from_fn(|i| HotbarItem::default());
+    let mut hotbar_list: [HotbarItem; (MAX_HOTBAR_ITEMS as usize)] = core::array::from_fn(|i| HotbarItem::default());
     let data = SrvSelectCharReply {
         race: looks.race as u8,
         map: position.map_id as u16,