Set default binary for cargo run

[Aakanksha638]

Demo

🎥 [Watch demo video](https://youtu.be/0frLn6aajUw)

Summary

Implements the full simple-chat specification in Rust using Tokio for async I/O.

• Non-blocking TCP server — each connection runs in its own tokio::spawn task
• Shared Room using Arc<Mutex<HashMap<String, UnboundedSender>>> to manage connected users
• Line-delimited JSON wire protocol with three client messages: join, send, leave
• Unique username enforcement — race-condition safe
• Messages broadcast to all users except the sender
• Graceful cleanup on both explicit leave and abrupt disconnect
• Interactive CLI client using tokio::select! to handle server messages and stdin simultaneously

Testing

• 11 unit tests — JSON round-trips for all protocol variants + Room logic in isolation
• 7 integration tests — real TCP connections on random OS-assigned ports covering join, broadcast, leave, duplicate username rejection, and send-before-join error

Bonus

• ✅ Pre-commit hook (.git-hooks/pre-commit) — blocks commit if cargo fmt, cargo build, or cargo clippy fail
• ✅ GitHub Actions CI (.github/workflows/ci.yml) — runs fmt + clippy + tests + end-to-end smoke test on every push

How to Run

# Start the server
cargo run --bin server -- --port 9000

# Connect as alice (new terminal)
cargo run --bin client -- --username alice --port 9000

# Connect as bob (new terminal)
cargo run --bin client -- --username bob --port 9000