feat(engine): in-game HUD — score, move count, elapsed time, mode badge

Adds HudPlugin with a persistent top-left overlay that shows score,
move count, and elapsed time during every game. A mode badge highlights
DAILY, CHALLENGE, ZEN, or TIME ATTACK when the game is not in Classic
mode. HUD updates whenever GameStateResource changes (moves and per-second
time ticks) without a separate polling system.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_app/src/main.rs

@@ -2,9 +2,9 @@ use bevy::prelude::*;
 use solitaire_data::{load_settings_from, provider_for_backend, settings_file_path, Settings};
 use solitaire_engine::{
     AchievementPlugin, AnimationPlugin, AudioPlugin, AutoCompletePlugin, CardPlugin,
-    ChallengePlugin, DailyChallengePlugin, GamePlugin, HelpPlugin, InputPlugin, LeaderboardPlugin,
-    OnboardingPlugin, PausePlugin, ProgressPlugin, SettingsPlugin, StatsPlugin, SyncPlugin,
-    TablePlugin, TimeAttackPlugin, WeeklyGoalsPlugin,
+    ChallengePlugin, DailyChallengePlugin, GamePlugin, HelpPlugin, HudPlugin, InputPlugin,
+    LeaderboardPlugin, OnboardingPlugin, PausePlugin, ProgressPlugin, SettingsPlugin, StatsPlugin,
+    SyncPlugin, TablePlugin, TimeAttackPlugin, WeeklyGoalsPlugin,
 };
 
 fn main() {
@@ -39,6 +39,7 @@ fn main() {
         .add_plugins(WeeklyGoalsPlugin)
         .add_plugins(ChallengePlugin)
         .add_plugins(TimeAttackPlugin)
+        .add_plugins(HudPlugin)
         .add_plugins(HelpPlugin)
         .add_plugins(PausePlugin)
         .add_plugins(SettingsPlugin::default())

solitaire_engine/src/hud_plugin.rs

@@ -0,0 +1,136 @@
+//! Persistent in-game HUD: score, move count, elapsed time, and mode badge.
+//!
+//! The HUD spawns once at startup and lives for the app's lifetime. Text is
+//! refreshed whenever `GameStateResource` changes (which happens on every move
+//! and every elapsed-time tick), so score, moves, and timer all stay current
+//! without a separate tick system.
+
+use bevy::prelude::*;
+use solitaire_core::game_state::GameMode;
+
+use crate::game_plugin::GameMutation;
+use crate::resources::GameStateResource;
+
+/// Marker on the score text node.
+#[derive(Component, Debug)]
+struct HudScore;
+
+/// Marker on the move-count text node.
+#[derive(Component, Debug)]
+struct HudMoves;
+
+/// Marker on the elapsed-time text node.
+#[derive(Component, Debug)]
+struct HudTime;
+
+/// Marker on the mode badge text node.
+#[derive(Component, Debug)]
+struct HudMode;
+
+/// HUD Z-layer — above cards (which start at z=0) but below overlay screens.
+const Z_HUD: i32 = 50;
+
+pub struct HudPlugin;
+
+impl Plugin for HudPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Startup, spawn_hud)
+            .add_systems(Update, update_hud.after(GameMutation));
+    }
+}
+
+fn spawn_hud(mut commands: Commands) {
+    let white = TextColor(Color::srgba(1.0, 1.0, 1.0, 0.80));
+    let font = TextFont { font_size: 18.0, ..default() };
+    commands
+        .spawn((
+            Node {
+                position_type: PositionType::Absolute,
+                left: Val::Px(12.0),
+                top: Val::Px(8.0),
+                flex_direction: FlexDirection::Row,
+                column_gap: Val::Px(20.0),
+                align_items: AlignItems::Center,
+                ..default()
+            },
+            ZIndex(Z_HUD),
+        ))
+        .with_children(|b| {
+            b.spawn((HudScore, Text::new("Score: 0"), font.clone(), white));
+            b.spawn((HudMoves, Text::new("Moves: 0"), font.clone(), white));
+            b.spawn((HudTime, Text::new("0:00"), font, white));
+            b.spawn((
+                HudMode,
+                Text::new(""),
+                TextFont { font_size: 17.0, ..default() },
+                TextColor(Color::srgb(1.0, 0.85, 0.25)),
+            ));
+        });
+}
+
+#[allow(clippy::type_complexity)]
+fn update_hud(
+    game: Res<GameStateResource>,
+    mut score_q: Query<&mut Text, (With<HudScore>, Without<HudMoves>, Without<HudTime>, Without<HudMode>)>,
+    mut moves_q: Query<&mut Text, (With<HudMoves>, Without<HudScore>, Without<HudTime>, Without<HudMode>)>,
+    mut time_q: Query<&mut Text, (With<HudTime>, Without<HudScore>, Without<HudMoves>, Without<HudMode>)>,
+    mut mode_q: Query<&mut Text, (With<HudMode>, Without<HudScore>, Without<HudMoves>, Without<HudTime>)>,
+) {
+    if !game.is_changed() {
+        return;
+    }
+
+    let g = &game.0;
+
+    if let Ok(mut t) = score_q.get_single_mut() {
+        **t = format!("Score: {}", g.score);
+    }
+    if let Ok(mut t) = moves_q.get_single_mut() {
+        **t = format!("Moves: {}", g.move_count);
+    }
+    if let Ok(mut t) = time_q.get_single_mut() {
+        let secs = g.elapsed_seconds;
+        let m = secs / 60;
+        let s = secs % 60;
+        **t = format!("{m}:{s:02}");
+    }
+    if let Ok(mut t) = mode_q.get_single_mut() {
+        **t = match g.mode {
+            GameMode::Classic => String::new(),
+            GameMode::Zen => "ZEN".to_string(),
+            GameMode::Challenge => "CHALLENGE".to_string(),
+            GameMode::TimeAttack => "TIME ATTACK".to_string(),
+        };
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::game_plugin::GamePlugin;
+    use crate::table_plugin::TablePlugin;
+    use solitaire_core::game_state::{DrawMode, GameState};
+
+    fn headless_app() -> App {
+        let mut app = App::new();
+        app.add_plugins(MinimalPlugins)
+            .add_plugins(GamePlugin)
+            .add_plugins(TablePlugin)
+            .add_plugins(HudPlugin);
+        app.update();
+        app
+    }
+
+    #[test]
+    fn hud_plugin_registers_without_panic() {
+        let _app = headless_app();
+    }
+
+    #[test]
+    fn update_hud_runs_after_game_mutation_without_panic() {
+        let mut app = headless_app();
+        app.world_mut().resource_mut::<GameStateResource>().0 =
+            GameState::new(42, DrawMode::DrawOne);
+        app.update();
+    }
+}

solitaire_engine/src/lib.rs

@@ -10,6 +10,7 @@ pub mod daily_challenge_plugin;
 pub mod events;
 pub mod game_plugin;
 pub mod help_plugin;
+pub mod hud_plugin;
 pub mod leaderboard_plugin;
 pub mod input_plugin;
 pub mod layout;
@@ -43,6 +44,7 @@ pub use events::{
 };
 pub use game_plugin::{GameMutation, GamePlugin, GameStatePath};
 pub use help_plugin::{HelpPlugin, HelpScreen};
+pub use hud_plugin::HudPlugin;
 pub use leaderboard_plugin::{LeaderboardPlugin, LeaderboardResource, LeaderboardScreen};
 pub use input_plugin::InputPlugin;
 pub use onboarding_plugin::{OnboardingPlugin, OnboardingScreen};