feat(lib): carry audio attributes in browse and folder listings

A browse listed each file as a name and a size, so a searcher who saw a
bitrate in a search reply lost it the moment they opened the sharer's
files. Listings (codes 5 and 37) now carry each file's attributes the
way Nicotine+ sends them, as a SharedFileEntry with name, size and
attributes in place of the (name, size) pair; the CLI's browse record
gains bitrate and duration, and the daemon protocol moves to version 2
for the new listing shape.

soulseek-rs-lib/src/actor/peer_actor/tests.rs

@@ -100,11 +100,10 @@ fn tick_reaps_a_peer_idle_past_the_deadline() {
 /// ticks proves the actor drains the socket rather than sipping 1 KiB a tick.
 fn big_listing() -> Vec<u8> {
     let files = (0..400u64)
-        .map(|i| {
-            (
-                format!("track-{i:03}-{}.flac", "x".repeat(i as usize % 17)),
-                i,
-            )
+        .map(|i| crate::message::peer::SharedFileEntry {
+            name: format!("track-{i:03}-{}.flac", "x".repeat(i as usize % 17)),
+            size: i,
+            attributes: Vec::new(),
         })
         .collect();
     let dir = crate::message::peer::SharedDirectory {