feat: browse your own shares as a peer receives them

The window could show any peer's share tree but never this account's, so
"am I actually sharing that?" had no answer short of asking a friend to
browse you. The tree is already there; what was missing was feeding it
from our own index.

B opens it — the same collapsible tree, filter, and navigation the peer
browse offers, built from `Shares::directories()`, which is the listing
GetShareFileList answers with. So what it shows is what the network sees,
not what the config meant to share. r re-scans the disk rather than
re-asking a peer, o steps across to the folders that feed it, and nothing
here queues a download from ourselves.

Attached to a daemon the index lives on the daemon's host, so it comes
back over a new `shares.files` method rather than being scanned locally;
`shares files [--filter]` prints the same listing headless, through the
`emit_listing` that `browse` now shares with it — the two are only
comparable while they are built the same way.

Two allocation fixes came out of the review, both on paths this reaches:
the daemon hands its listing to the DTO instead of deep-copying one it
already owns, and `Shares::directories()` allocates its map key once per
folder rather than once per file, which the peer-facing serve path has
been paying for all along.

soulseek-rs/src/remote/mod.rs

@@ -14,8 +14,8 @@ use crate::daemon::proto::{
     DownloadStartParams, DownloadStarted, Downloads, Event, IntervalSeconds,
     MemberStats, Members, MessageParams, Messages, Method, PROTOCOL_VERSION,
     PasswordParams, QueryParams, Request, Response, RoomRef, RpcError,
-    SayParams, SearchResults, Searches, Seconds, SharesStatus, SlotsParams,
-    TransferRef, Uploads, UserRef, UserResult, Watched,
+    SayParams, SearchResults, Searches, Seconds, SharedListing, SharesStatus,
+    SlotsParams, TransferRef, Uploads, UserRef, UserResult, Watched,
 };
 use mirror::Mirror;
 use serde::de::DeserializeOwned;
@@ -823,6 +823,18 @@ impl SessionApi for RemoteSession {
         self.shares().directories
     }
 
+    // ponytail: a blocking round-trip that carries the whole index — a very
+    // large share is tens of MB of JSON before the next redraw. It is only
+    // ever a keypress, never a frame; if that stops being tolerable, push it
+    // as an event the way `browse.user` answers with `event.browse`.
+    fn shared_listing(&self) -> Vec<SharedDirectory> {
+        self.request::<_, SharedListing>(Method::SharesFiles, ())
+            .map(|listing| {
+                listing.directories.into_iter().map(Into::into).collect()
+            })
+            .unwrap_or_default()
+    }
+
     fn set_shared_directories(&self, directories: Vec<String>) -> Result<()> {
         self.tell(Method::SharesSet, DirectoriesParams { directories })
     }