Baseline: full tree snapshot after git repository loss

The previous .git directory was found gutted (only info/ remained), so
history is unrecoverable locally. This commit restores version control
with the tree exactly as it stands: the working app, the preview-tracks
launcher on the artist hero, the scrollable-track-previews design bundle
(docs + approved mockups), and the Phase 0 validation artifacts.

crates/soulseek-proto/src/lib.rs

@@ -0,0 +1,31 @@
+//! Soulseek protocol messages and binary codecs.
+//!
+//! Wire format: every message is `[u32 length][code][payload]`, little-endian
+//! throughout. Server and peer messages use a `u32` code; connection
+//! initialization messages (PeerInit / PierceFirewall) use a single-byte code.
+//! Strings are `[u32 len][bytes]`, UTF-8 with Latin-1 fallback on decode.
+//! Search responses and browse payloads are zlib-compressed after the code.
+//!
+//! Reference: Soulseek.NET `src/Messaging/**` and the Nicotine+ protocol docs.
+
+pub mod dist;
+pub mod peer;
+pub mod server;
+pub mod types;
+pub mod wire;
+
+#[derive(Debug, thiserror::Error)]
+pub enum ProtoError {
+    #[error("message payload ended unexpectedly")]
+    UnexpectedEof,
+    #[error("zlib decompression failed: {0}")]
+    Zlib(#[from] std::io::Error),
+    #[error("message too large: {0} bytes")]
+    TooLarge(usize),
+}
+
+pub type Result<T> = std::result::Result<T, ProtoError>;
+
+/// Sanity cap on a single message frame (search responses from big shares
+/// run a few hundred KB; browse responses can reach tens of MB).
+pub const MAX_MESSAGE_SIZE: usize = 64 * 1024 * 1024;