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/src/ui/panes/mod.rs

@@ -1,4 +1,5 @@
 mod browse_pane;
+mod chat_pane;
 mod download_info_pane;
 mod downloads_pane;
 mod results_pane;
@@ -6,7 +7,8 @@ mod rooms_pane;
 mod searches_pane;
 
 pub use browse_pane::render_browse_pane;
-pub use download_info_pane::render_download_info_pane;
+pub use chat_pane::render_chat_pane;
+pub use download_info_pane::{render_download_info_pane, selected_transfer};
 pub use downloads_pane::render_downloads_pane;
 pub use results_pane::{ResultsPaneParams, render_results_pane};
 pub use rooms_pane::render_rooms_pane;