feat!: wishlist, upload-queue privilege recognition, and search filters (#20)

Closes the last two gaps in Soulseek's list of features an alternative client
must implement to be tolerated, and adds the result filters Nicotine+ has had
all along.

Wishlist: server code 103 is sent and code 104's announced interval is kept
rather than logged and discarded, so the re-search timer runs off the schedule
the server set. `wish add|remove|list|run` plus `serve --wishlist`; wishes
persist in config.toml as a TOML array so a comma inside a query survives.
`wish run` prints search-shaped records, so it pipes into `download --stdin`.

Privilege recognition: the code-69 user list is parsed instead of counted and
dropped, and code 92 answers `whoami` as `privilege_seconds`. Uploads now go
through a queue with a slot cap (`--upload-slots`, default 2) that serves
privileged users first — the cap is what makes the ordering mean anything, so
they are one change. `PlaceInQueueRequest` (peer code 51) is answered, where it
previously had no handler at all, and a departed peer's slot is released so a
stalled peer cannot wedge uploads shut.

Search filters: `--exclude`, `--extension`, `--min-size`, `--max-size` beside
the existing `--min-bitrate` and `--free-slots`, in one flattened arg group
shared by `search`, `get` and `wish run`.

Also serialises the library e2e suite behind the same gate `cli_e2e` already
uses: the new queue tests hold peer sockets open on purpose, which starved
concurrently-spawned soulfinds and failed unrelated download tests with
`login: Timeout`.

BREAKING CHANGE: `UploadStatus` gains a `Queued(u32)` variant, so an exhaustive
match on it no longer compiles, and `cli::Commands` gains `Wish`.

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

@@ -2,9 +2,10 @@ use crate::actor::{Actor, ActorHandle, ConnectionState};
 use crate::client::ClientOperation;
 use crate::dispatcher::MessageDispatcher;
 use crate::message::peer::{
-    FileSearchResponse, GetShareFileList, PeerInit, PlaceInQueueResponse,
-    QueueUploadHandler, SharedDirectory, SharedFileListResponseHandler,
-    TransferRequest, TransferResponse, UploadFailedHandler,
+    FileSearchResponse, GetShareFileList, PeerInit, PlaceInQueueRequest,
+    PlaceInQueueResponse, QueueUploadHandler, SharedDirectory,
+    SharedFileListResponseHandler, TransferRequest, TransferResponse,
+    UploadFailedHandler,
 };
 use crate::message::server::MessageFactory;
 use crate::message::{Handlers, Message, MessageReader, MessageType};
@@ -39,6 +40,8 @@ pub enum PeerMessage {
     RequestTransfer(Download),
     /// A peer queued one of our shared files for download (they sent us code 43).
     IncomingQueueUpload(String),
+    /// A peer asked where their queued file sits (they sent us code 51).
+    IncomingPlaceInQueueRequest(String),
     /// A peer asked to browse our shared files (they sent us code 4).
     ShareListRequested,
     /// A peer we are browsing sent us their shared-file listing (code 5).
@@ -164,6 +167,7 @@ impl PeerActor {
         handlers.register_handler(TransferResponse);
         handlers.register_handler(GetShareFileList);
         handlers.register_handler(UploadFailedHandler);
+        handlers.register_handler(PlaceInQueueRequest);
         handlers.register_handler(PlaceInQueueResponse);
         handlers.register_handler(QueueUploadHandler);
         handlers.register_handler(SharedFileListResponseHandler);
@@ -235,6 +239,20 @@ impl PeerActor {
             PeerMessage::IncomingQueueUpload(filename) => {
                 self.handle_incoming_queue_upload(filename);
             }
+            PeerMessage::IncomingPlaceInQueueRequest(filename) => {
+                let requester_key = self.peer_username();
+                if let Err(e) = self.client_channel.send(
+                    ClientOperation::PlaceInQueueRequested {
+                        requester_key,
+                        filename,
+                    },
+                ) {
+                    error!(
+                        "[peer_actor] forward IncomingPlaceInQueueRequest: {}",
+                        e
+                    );
+                }
+            }
             PeerMessage::ServeUpload {
                 token,
                 filename,