Show the passage during the countdown, and fix navigation across screens

Countdown
- Five seconds instead of three, and shown over the passage on the race
  screen rather than in an empty lobby. New ServerMessage::RaceText carries
  the text (and its attribution) just before the countdown starts, so every
  client can put it on screen and let players read the opening words while
  the numbers run - what TypeRacer and 10FastFingers both do. Typing is
  locked until Start lifts the gate.
- Two subscriptions had to move with it. Building the race view tears the
  lobby down, and the lobby owned the only handlers for Countdown and Start,
  so the count stopped arriving exactly when it was needed and the gate would
  never have lifted.
- The TUI and Steam clients match ServerMessage exhaustively, so both gained
  an arm for the new variant; whole workspace checks clean.

Multiplayer attribution
- Race passages now carry who wrote them, so a race shows its source the way
  single player always has. Previously the server sent bare strings and both
  the race and its end screen showed nothing.

Navigation
- Every screen's full-width "Back" button becomes a close control at the top
  of the content. The wordmark and Escape already went back, so it was a
  third way to do the same thing and the least reachable of them.
- The multiplayer screen had a Back button on top of that; gone.

Fixes
- The end screen graph is drawn into a canvas, so it cannot inherit a theme
  change the way the rest of the page does. It now redraws on one - switching
  theme used to leave the chart in the old palette.
- .stats-empty was align-self:flex-start inside a centred column, so "Sign in
  to add friends" sat on a different axis from its own Sign In button.
- The store showed a sign-in prompt instead of its catalogue, so nobody could
  see what signing in would get them. The catalogue now renders signed out,
  with prices, behind a sign-in note.
- The room code field is sized for the five characters a code actually is,
  and Join carries the same weight as the field it belongs to.

3 files changed, 48 insertions, 12 deletions

diff --git a/crates/server/src/main.rs b/crates/server/src/main.rs
index 7e9e9a8..2769d4a 100644
--- a/crates/server/src/main.rs
+++ b/crates/server/src/main.rs
@@ -10,6 +10,7 @@ mod spotify;
 mod state;
 mod stats;
 
+use crate::state::RaceText;
 use axum::http::{HeaderValue, Method};
 use axum::routing::get;
 use axum::Router;
@@ -24,6 +25,8 @@ use tower_http::trace::TraceLayer;
 #[derive(Deserialize)]
 struct TextEntry {
     content: String,
+    #[serde(default)]
+    attribution: Option<String>,
 }
 
 // Every multiplayer room draws from this same pool so every player in a
@@ -32,15 +35,18 @@ struct TextEntry {
 // falls back to a couple of plain sentences if the file isn't reachable
 // (e.g. the server binary run from somewhere other than the repo root),
 // so a room can still start rather than erroring on an empty pool.
-fn load_race_texts() -> Vec<String> {
+fn load_race_texts() -> Vec<RaceText> {
     let path = std::env::var("TEXTS_JSON_PATH").unwrap_or_else(|_| "texts.json".to_string());
     match std::fs::read_to_string(&path).ok().and_then(|raw| serde_json::from_str::<Vec<TextEntry>>(&raw).ok()) {
-        Some(entries) if !entries.is_empty() => entries.into_iter().map(|e| e.content).collect(),
+        Some(entries) if !entries.is_empty() => entries
+            .into_iter()
+            .map(|e| RaceText { text: e.content, attribution: e.attribution })
+            .collect(),
         _ => {
             tracing::warn!("could not load race texts from {path} - using a small built-in fallback pool");
             vec![
-                "The quick brown fox jumps over the lazy dog.".to_string(),
-                "Pack my box with five dozen liquor jugs.".to_string(),
+                RaceText { text: "The quick brown fox jumps over the lazy dog.".to_string(), attribution: None },
+                RaceText { text: "Pack my box with five dozen liquor jugs.".to_string(), attribution: None },
             ]
         }
     }
@@ -136,7 +142,10 @@ mod tests {
         let app_state = Arc::new(AppState::new(
             db,
             false,
-            vec!["The quick brown fox jumps over the lazy dog.".to_string()],
+            vec![RaceText {
+                text: "The quick brown fox jumps over the lazy dog.".to_string(),
+                attribution: None,
+            }],
             SpotifyConfig::default(),
             "http://localhost:4173".to_string(),
         ));
diff --git a/crates/server/src/multiplayer.rs b/crates/server/src/multiplayer.rs
index 8974c8c..7fca7c3 100644
--- a/crates/server/src/multiplayer.rs
+++ b/crates/server/src/multiplayer.rs
@@ -56,6 +56,10 @@ const BOT_NAMES: &[&str] = &[
     "Pixel", "Quartz", "Sigil", "Tessa", "Umbra",
 ];
 
+// Long enough to read the passage's opening words and get your hands in
+// position. Three seconds was barely enough to register that a race had
+// started, let alone look at the text.
+const COUNTDOWN_SECONDS: u32 = 5;
 const ROOM_CODE_CHARS: &[u8] = b"ABCDEFGHJKLMNPQRSTUVWXYZ23456789"; // no 0/O/1/I - easy to misread aloud
 
 #[derive(Debug, Clone, PartialEq)]
@@ -318,16 +322,30 @@ async fn start_race(room_arc: Arc<Mutex<Room>>, state: Arc<AppState>) {
             return;
         }
         room.status = RoomStatus::Countdown;
-        let text = state
+        let picked = state
             .race_texts
             .get(rand::thread_rng().gen_range(0..state.race_texts.len()))
             .cloned()
-            .unwrap_or_default();
-        room.text = Some(text.clone());
-        text
+            .unwrap_or_else(|| crate::state::RaceText {
+                text: String::new(),
+                attribution: None,
+            });
+        room.text = Some(picked.text.clone());
+        // Sent before the countdown so every client can put the passage on
+        // screen and let players read it while they wait, the way TypeRacer
+        // and 10FastFingers both do.
+        broadcast(
+            &room,
+            &ServerMessage::RaceText {
+                text: picked.text.clone(),
+                attribution: picked.attribution.clone(),
+            },
+        )
+        .await;
+        picked.text
     };
 
-    for seconds in (1..=3).rev() {
+    for seconds in (1..=COUNTDOWN_SECONDS).rev() {
         {
             let room = room_arc.lock().await;
             broadcast(&room, &ServerMessage::Countdown { seconds }).await;
diff --git a/crates/server/src/state.rs b/crates/server/src/state.rs
index 267b6fb..7244955 100644
--- a/crates/server/src/state.rs
+++ b/crates/server/src/state.rs
@@ -17,6 +17,15 @@ impl SpotifyConfig {
     }
 }
 
+/// A passage a race can be run on, with whoever wrote it. The attribution
+/// travels with the text so every racer can see where the passage came from,
+/// the same way single player does.
+#[derive(Debug, Clone)]
+pub struct RaceText {
+    pub text: String,
+    pub attribution: Option<String>,
+}
+
 #[derive(Clone)]
 pub struct AppState {
     pub db: SqlitePool,
@@ -33,7 +42,7 @@ pub struct AppState {
     /// Race passages every multiplayer room draws from, so every player in
     /// a room types the identical text - loaded once at startup rather
     /// than per-room, since the pool itself never changes at runtime.
-    pub race_texts: Vec<String>,
+    pub race_texts: Vec<RaceText>,
     pub spotify: SpotifyConfig,
     pub frontend_origin: String,
     pub http: Client,
@@ -43,7 +52,7 @@ impl AppState {
     pub fn new(
         db: SqlitePool,
         cookie_secure: bool,
-        race_texts: Vec<String>,
+        race_texts: Vec<RaceText>,
         spotify: SpotifyConfig,
         frontend_origin: String,
     ) -> Self {