feat(rooms): private room membership, operators and refusals

Private rooms were unreachable: the client could ask to join one but had
no way to invite, promote, resign or be told what happened, and a room
name already owned by someone else came back as silence rather than a
refusal (code 1003).

Adds the rosters the server pushes after login (133/148), the changes it
narrates to them (134/135, 143/144), our own standing (139/140, 145/146),
and the messages that drive them, with the rosters kept current in client
state. The daemon protocol and the TUI room transcript carry the new
events rather than dropping them.

soulseek-rs-lib/src/client/social.rs

@@ -21,6 +21,137 @@ impl Client {
         self.send_server_message(MessageFactory::build_server_ping())
     }
 
+    /// Join a private room, creating it (and owning it) if the name is free.
+    ///
+    /// A name already taken by someone else's private room comes back as a
+    /// [`crate::RoomEvent::CantCreate`] rather than a join.
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn join_private_room(&self, room: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_join_room(room, true))
+    }
+
+    /// Invite `username` into the private room we own (code 134).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn add_room_member(&self, room: &str, username: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_add_room_member(
+            room, username,
+        ))
+    }
+
+    /// Remove `username` from the private room we own (code 135).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn remove_room_member(&self, room: &str, username: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_remove_room_member(
+            room, username,
+        ))
+    }
+
+    /// Give up our own membership of a private room (code 136).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn leave_private_room(&self, room: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_cancel_room_membership(
+            room,
+        ))
+    }
+
+    /// Give up ownership of a private room, which deletes it (code 137).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn disband_private_room(&self, room: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_cancel_room_ownership(
+            room,
+        ))
+    }
+
+    /// Say whether we accept private-room invitations (code 141).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn set_room_invitations_enabled(&self, enabled: bool) -> Result<()> {
+        self.send_server_message(MessageFactory::build_enable_room_invitations(
+            enabled,
+        ))
+    }
+
+    /// Make `username` an operator of our private room (code 143).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn add_room_operator(&self, room: &str, username: &str) -> Result<()> {
+        self.send_server_message(MessageFactory::build_add_room_operator(
+            room, username,
+        ))
+    }
+
+    /// Take operator status away from `username` (code 144).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn remove_room_operator(
+        &self,
+        room: &str,
+        username: &str,
+    ) -> Result<()> {
+        self.send_server_message(MessageFactory::build_remove_room_operator(
+            room, username,
+        ))
+    }
+
+    /// Give up our own operator status in `room` (code 147).
+    ///
+    /// # Errors
+    /// [`crate::SoulseekRs::NotConnected`] when there is no server connection.
+    pub fn resign_room_operatorship(&self, room: &str) -> Result<()> {
+        self.send_server_message(
+            MessageFactory::build_cancel_room_operatorship(room),
+        )
+    }
+
+    /// Who may enter the private room `room`, as the server last reported.
+    #[must_use]
+    pub fn private_room_members(&self, room: &str) -> Vec<String> {
+        match self.context.read_safe() {
+            Ok(ctx) => ctx.private_room_members(room),
+            Err(e) => {
+                error!("[client] private_room_members: {}", e);
+                Vec::new()
+            }
+        }
+    }
+
+    /// Who runs the private room `room`.
+    #[must_use]
+    pub fn private_room_operators(&self, room: &str) -> Vec<String> {
+        match self.context.read_safe() {
+            Ok(ctx) => ctx.private_room_operators(room),
+            Err(e) => {
+                error!("[client] private_room_operators: {}", e);
+                Vec::new()
+            }
+        }
+    }
+
+    /// The private rooms we belong to.
+    #[must_use]
+    pub fn private_rooms(&self) -> Vec<String> {
+        match self.context.read_safe() {
+            Ok(ctx) => ctx.private_rooms(),
+            Err(e) => {
+                error!("[client] private_rooms: {}", e);
+                Vec::new()
+            }
+        }
+    }
+
     /// Set our online status (server code 28): away, or back to online.
     ///
     /// Other clients see it in their `GetUserStatus` and watch replies, and