fix(peer): serve full browse listings + harden the listener; TUI transfer/UX work

Peer layer:
- Stream peer messages with a partial-write queue instead of write_all, so a
  large SharedFileListResponse over the non-blocking socket is no longer
  truncated (third-party clients like SoulseekQt can now browse our shares).
- Bound the peer-init handshake with a read timeout and handle each accepted
  connection on its own thread, so one stalled peer can't wedge the listener.
- e2e: third-party direct/brokered/large-share browse + stalled-peer coverage.

TUI:
- Uploads share the downloads table columns (real Speed) and the info pane now
  renders details for a selected upload.
- Download progress bar counts only in-progress transfers and hides when idle.
- Always-visible unread badge (private messages + rooms) in the shortcuts bar,
  self-drawn blink so it works under tmux.
- Persist the unread private-message count across restarts.

soulseek-rs-lib/src/types.rs

@@ -271,4 +271,7 @@ pub struct UploadInfo {
     pub size: u64,
     pub bytes_sent: u64,
     pub status: UploadStatus,
+    /// Transfer rate, so an upload row can fill the same Speed column a
+    /// download does. Zero unless the upload is in progress.
+    pub speed_bytes_per_sec: f64,
 }