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

character-service/build.rs

@@ -5,10 +5,7 @@ fn main() {
         .compile_well_known_types(true)
         .type_attribute(".", "#[derive(serde::Serialize, serde::Deserialize)]")
         .compile_protos(
-            &[
-                "../proto/character_common.proto",
-                "../proto/character.proto",
-            ],
+            &["../proto/character_common.proto", "../proto/character.proto"],
             &["../proto"],
         )
         .unwrap_or_else(|e| panic!("Failed to compile protos {:?}", e));