Reconnect the game websocket after connectivity loss

The socket had no recovery path: a mid-game drop left the table showing
stale state with no indication, and plays were silently swallowed by the
dead channel. Surface the server close code from ws::connect and add a
reconnect driver in the game page: transient losses retry with
exponential backoff (capped, then a manual Retry), while deliberate
closes (session expired, game gone) stop retrying. Reconnects are free
resyncs because the server pushes a full state snapshot on connect.

Also gate card clicks while disconnected, show a connection banner, and
drop the ticking interval and pending retries on unmount.

web/src/ws.rs

@@ -4,7 +4,7 @@ use std::rc::Rc;
 
 use futures::channel::mpsc;
 use futures::{SinkExt, StreamExt};
-use gloo_net::websocket::{futures::WebSocket, Message};
+use gloo_net::websocket::{futures::WebSocket, Message, WebSocketError};
 use wasm_bindgen_futures::spawn_local;
 
 use crate::model::ServerMessage;
@@ -53,10 +53,14 @@ impl GameSocket {
 /// Open the websocket for `game_id` and forward parsed server messages to
 /// `on_message`. Returns the socket handle, or `None` if the connection
 /// could not be created.
+///
+/// `on_close` fires exactly once when the connection ends; it receives the
+/// server close code when one was sent (e.g. 4401 unauthenticated, 4403 not
+/// seated, 4404 unknown game) or `None` for an abnormal network loss.
 pub fn connect(
     game_id: &str,
     on_message: impl Fn(ServerMessage) + 'static,
-    on_close: impl Fn() + 'static,
+    on_close: impl Fn(Option<u16>) + 'static,
 ) -> Option<GameSocket> {
     let ws = WebSocket::open(&ws_url(game_id)).ok()?;
     let (mut write, mut read) = ws.split();
@@ -72,6 +76,7 @@ pub fn connect(
     });
 
     spawn_local(async move {
+        let mut close_code = None;
         while let Some(msg) = read.next().await {
             match msg {
                 Ok(Message::Text(text)) => {
@@ -80,10 +85,14 @@ pub fn connect(
                     }
                 }
                 Ok(Message::Bytes(_)) => {}
+                Err(WebSocketError::ConnectionClose(e)) => {
+                    close_code = Some(e.code);
+                    break;
+                }
                 Err(_) => break,
             }
         }
-        on_close();
+        on_close(close_code);
     });
 
     Some(GameSocket {