feat(daemon): make the download folder a live setting in both modes

The full-surface audit found the settings story half-true: `config set
download_dir` and the TUI's settings form edited a file a running daemon
never rereads, while the attached TUI displayed the laptop's path and
discarded the edit entirely.

- `download.set_dir`: a session-wide move, published in the contract;
  the per-transfer destination stays refused. `daemon.status` reports
  it and the next transfer lands there.
- `config set download_dir` and `config set shared_dirs` push to a
  live daemon the way `shares add` does, through one shared helper;
  the socket probe is paid only by the keys a daemon owns.
- The attached TUI seeds its settings form from the daemon's status,
  pushes both folders over the socket as typed, reports a partial
  refusal as exactly that, and creates no client-side directories. It
  reads the daemon token from the resolved config — with the token only
  in config.toml it could not attach over TCP — and settings
  persistence honours --config instead of hard-coding the default path.
- `search.wishlist` records a start time, so an attached window
  renders it as running rather than instantly finished.

The rest is the coverage the audit demanded: CLI-level token auth
(wrong, missing, and valid over TCP), `daemon status|stop` with
nothing running, --sort, --limit, --pick first, --password-cmd,
--log-file, --upload-slots, the config-named download folder in both
modes, and headless settings-form tests attached and local. Every
guard was checked by disabling what it protects. Both e2e modes run
green: 94 CLI tests each way, 16 protocol, 285 unit, 34 lib.

soulseek-rs/src/remote/mod.rs

@@ -10,11 +10,12 @@ mod mirror;
 use crate::api::{SessionApi, SessionSearch};
 use crate::daemon::proto::{
     Ack, AuthParams, AuthResult, CODE_APPLICATION, ChatMessageDto,
-    DaemonStatus, DirectoriesParams, DownloadDto, DownloadStartParams,
-    DownloadStarted, Downloads, Event, IntervalSeconds, Members, MessageParams,
-    Messages, Method, PROTOCOL_VERSION, QueryParams, Request, Response,
-    RoomRef, RpcError, SayParams, SearchResults, Searches, Seconds,
-    SharesStatus, SlotsParams, TransferRef, Uploads, UserRef, UserResult,
+    DaemonStatus, DirectoriesParams, DirectoryParams, DownloadDto,
+    DownloadStartParams, DownloadStarted, Downloads, Event, IntervalSeconds,
+    Members, MessageParams, Messages, Method, PROTOCOL_VERSION, QueryParams,
+    Request, Response, RoomRef, RpcError, SayParams, SearchResults, Searches,
+    Seconds, SharesStatus, SlotsParams, TransferRef, Uploads, UserRef,
+    UserResult,
 };
 use mirror::Mirror;
 use serde::de::DeserializeOwned;
@@ -781,6 +782,10 @@ impl SessionApi for RemoteSession {
     fn set_shared_directories(&self, directories: Vec<String>) -> Result<()> {
         self.tell(Method::SharesSet, DirectoriesParams { directories })
     }
+
+    fn set_download_directory(&self, directory: String) -> Result<()> {
+        self.tell(Method::DownloadSetDir, DirectoryParams { directory })
+    }
 }
 
 #[cfg(test)]