# Milestone 1: The Foundation (The Skeleton)
**Goal:** Initialize the project and establish the shared language between client and server.

### 1. Workspace Setup
- [x] Initialize the root Cargo workspace: `cargo init --vcs none` (delete `src/`). Create a root `Cargo.toml` with `[workspace] members = ["core_protocol", "server_node", "client_node"]`.
- [x] **AI Context Trap (File Structure):** Strictly adhere to the directory layout and module hierarchy defined in `File_Structure.md`. Do not invent new file paths or module names; map every new crate and file exactly to the blueprint.
- [x] Create crates: `cargo new --lib core_protocol`, `cargo new --bin server_node`, `cargo new --bin client_node`.
- [x] Add strict lints (`#![forbid(unsafe_code)]`, etc.) to the root workspace or individual `lib.rs`/`main.rs` files.
- [x] **Dependencies (`core_protocol`):** Add `serde`, `bincode`, `uuid`, `chrono`, `thiserror`, `secrecy` (for zeroing sensitive keys).
- [x] **Dependencies (`server_node`):** Add `tokio` (full), `tracing`, `tracing-subscriber`, `anyhow`, `dashmap`, `tokio-util`, `tokio-serde`, `futures`.
- [x] **Dependencies (`client_node`):** Add `tokio` (rt-multi-thread), `tracing`, `tracing-subscriber`, `anyhow`, `tokio-util`, `tokio-serde`, `futures`.

### 2. Protocol Definitions (`core_protocol`)
- [x] Create `src/tcp_events.rs`. Define `enum TcpEvent { AuthRequest { username: String, ... }, AuthResponse { session_token: u32, ... }, ChannelJoin { ... }, ChatMessage { ... } }` with `#[derive(Serialize, Deserialize)]`.
- [x] Create `src/udp_packets.rs`. Define `struct VoicePacketHeader { pub session_token: u32, pub sequence_num: u64, pub timestamp: u64 }` with `#[derive(Serialize, Deserialize)]`.
- [x] Create `src/constants.rs`. Define `pub const SAMPLE_RATE: u32 = 48000;`, `pub const FRAME_SIZE: usize = 960;`, `pub const TCP_PORT: u16 = 8080;`.

### 3. TCP Handshake (`server_node` & `client_node`)
- [x] **Server:** In `server_node/src/main.rs`, initialize `tokio::net::TcpListener::bind("0.0.0.0:8080")`.
- [x] **Server:** Spawn a new `tokio::spawn(async move { ... })` for each incoming `TcpStream`.
- [x] **Client:** In `client_node/src/network/control.rs`, implement `TcpStream::connect("127.0.0.1:8080")`.
- [x] **AI Context Trap (TCP Framing):** Raw TCP streams suffer from fragmentation. Do NOT attempt to manually buffer bytes. You must use `tokio_util::codec::LengthDelimitedCodec` (with `tokio_serde` and `bincode`) to abstract the frame boundaries cleanly.

### 4. Login Logic & State
- [x] **Server State:** Create `server_node/src/state.rs`. Define a `DashMap<u32, UserState>` to store active session tokens.
- [x] **Authentication Flow:** Client sends `TcpEvent::AuthRequest`. Server generates a sequential `u32` session token (via `AtomicU32`), stores it in `DashMap`, and returns `TcpEvent::AuthResponse`.
- [x] **Validation:** Ensure the server actively drops the connection if the client sends invalid or excessively large payloads.

### 5. Observability (Logging)
- [x] **Initialization:** In both binaries' `main.rs`, call `tracing_subscriber::fmt::init()`.
- [x] **Implementation:** Replace all `println!` calls with `tracing::info!`, `tracing::warn!`, or `tracing::error!`.
- [x] **Tracing Context:** Use `#[tracing::instrument]` on core TCP handler functions to automatically log client IPs and session IDs.