Finalization and assembly of the finished game on Unity - online cooperative roguelite with Steamworks

There is an almost finished game (PC, Unity 2022.3 LTS, URP) in the top-down roguelite genre. Now the single-player mode is working stably, the content and UI are about 80% ready. Требуется довести проект до состояния готовой сборки с рабочим сетевым кооперативом на 2-4 игроков и корректной интеграцией со Steam.

Initial situation
- Unity project in Git (I will provide the repository), there are scenes: MainMenu, Lobby, Game, Results

- Used Cinemachine, Addressables (partially), new Input System

What needs to be done

Limitations and technical environment
- Unity 2022.3 LTS, C#, URP

Measurable acceptance criteria
1) 4 players can create a lobby on Steam, send an invitation, connect and start the match synchronously
2) In a 20-minute test run for 4 players, there are no critical desynchronizations - everyone has the same wave results, the state of the doors, the composition of the loot, the final screen is the same
3) Picking up items is not duplicated or lost - one item can only be picked up by one player, the state is correctly replicated
4) After a wipe of the entire group or a victory, a correct transition to Results occurs for all clients, without freezing and re-downloads
5) The repository has a short README - how to launch 2-4 instances locally, how to test via Steam (Spacewar AppID is acceptable for testing)

Intermediate stages
- Audit of the current network layer and proposed authority/synchronization scheme (short plan before the start of active code rewrite)
- Implementation of Steam lobby/invites and basic connection
- Match synchronization and desync fixes
- Final stabilization, assembly, README, small test checklist

Result
- A repository with a working online co-op, Steam invites and a finished Windows build that passes the acceptance criteria.