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/daemon/server/mod.rs

@@ -13,8 +13,9 @@ use super::proto::{
     MemberStats, Members, MessageParams, Messages, Method, OPENRPC,
     PROTOCOL_VERSION, PasswordParams, QueryParams, RoomRef, RoomUserStatsDto,
     RpcError, SayParams, SearchResultDto, SearchResults, SearchSummary,
-    Searches, Seconds, SharesStatus, SlotsParams, TransferRef, UploadInfoDto,
-    Uploads, UserInfoDto, UserRef, UserResult, Watched,
+    Searches, Seconds, SharedDirectoryDto, SharedListing, SharesStatus,
+    SlotsParams, TransferRef, UploadInfoDto, Uploads, UserInfoDto, UserRef,
+    UserResult, Watched,
 };
 use crate::api::SessionApi;
 use crate::output::Exit;
@@ -372,6 +373,14 @@ impl Daemon {
             }
 
             Method::SharesStatusOf => ok(self.shares()),
+            Method::SharesFiles => ok(SharedListing {
+                directories: self
+                    .session
+                    .shared_listing()
+                    .into_iter()
+                    .map(SharedDirectoryDto::from)
+                    .collect(),
+            }),
             Method::SharesSet => {
                 let directories: DirectoriesParams = parse(params)?;
                 self.session
@@ -1018,6 +1027,9 @@ mod tests {
         fn shared_counts(&self) -> (u32, u32) {
             (0, 0)
         }
+        fn shared_listing(&self) -> Vec<soulseek_rs::SharedDirectory> {
+            Vec::new()
+        }
         fn shared_directories(&self) -> Vec<String> {
             Vec::new()
         }