refactor(core): derive Copy for DrawMode; drop redundant .clone() calls (M-18)

DrawMode is a fieldless two-variant enum — it is trivially bitwise-
copyable. Adding Copy + updating choose_winnable_seed to take the value
directly eliminates 13 superfluous .clone() calls across solitaire_core,
solitaire_engine, solitaire_assetgen, and solitaire_wasm.

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

solitaire_assetgen/src/bin/gen_difficulty_seeds.rs

@@ -96,7 +96,7 @@ fn main() {
                 continue;
             }
             let cfg = SolverConfig { move_budget, state_budget };
-            match try_solve(seed, draw_mode.clone(), &cfg) {
+            match try_solve(seed, draw_mode, &cfg) {
                 SolverResult::Winnable => {
                     buckets[i].push(seed);
                     eprintln!(

solitaire_assetgen/src/bin/gen_seeds.rs

@@ -73,7 +73,7 @@ fn main() {
     while found.len() < count {
         tried += 1;
         if matches!(
-            try_solve(seed, draw_mode.clone(), &cfg),
+            try_solve(seed, draw_mode, &cfg),
             SolverResult::Winnable
         ) {
             found.push(seed);

solitaire_core/src/game_state.rs

@@ -43,7 +43,7 @@ mod pile_map_serde {
 }
 
 /// Whether cards are drawn one at a time or three at a time from the stock.
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 pub enum DrawMode {
     /// Draw one card from stock per turn.
     DrawOne,

solitaire_core/src/solver.rs

@@ -665,7 +665,7 @@ impl SolverState {
             foundation,
             stock,
             waste,
-            draw_mode: game.draw_mode.clone(),
+            draw_mode: game.draw_mode,
             just_drew: false,
             consecutive_draws: 0,
         }

solitaire_engine/src/game_plugin.rs

@@ -380,11 +380,11 @@ fn poll_pending_new_game_seed(
 
 /// Pure helper extracted for testability — `new_game_with_solver_*`
 /// engine tests in the same file exercise this path.
-pub(crate) fn choose_winnable_seed(initial_seed: u64, draw_mode: &DrawMode) -> u64 {
+pub(crate) fn choose_winnable_seed(initial_seed: u64, draw_mode: DrawMode) -> u64 {
     let cfg = SolverConfig::default();
     let mut seed = initial_seed;
     for _ in 0..SOLVER_DEAL_RETRY_CAP {
-        match try_solve(seed, draw_mode.clone(), &cfg) {
+        match try_solve(seed, draw_mode, &cfg) {
             SolverResult::Winnable | SolverResult::Inconclusive => return seed,
             SolverResult::Unwinnable => {
                 seed = seed.wrapping_add(1);
@@ -451,7 +451,7 @@ fn handle_new_game(
         // where SettingsPlugin is not installed.
         let draw_mode = settings
             .as_ref()
-            .map_or_else(|| game.0.draw_mode.clone(), |s| s.0.draw_mode.clone());
+            .map_or_else(|| game.0.draw_mode, |s| s.0.draw_mode);
         let mode = ev.mode.unwrap_or(game.0.mode);
 
         // Solver-backed retry: when the player has opted in to
@@ -473,9 +473,8 @@ fn handle_new_game(
             .as_ref()
             .is_some_and(|s| s.0.winnable_deals_only);
         if winnable_only && mode == GameMode::Classic && ev.seed.is_none() {
-            let dm = draw_mode.clone();
             let task = AsyncComputeTaskPool::get()
-                .spawn(async move { choose_winnable_seed(initial_seed, &dm) });
+                .spawn(async move { choose_winnable_seed(initial_seed, draw_mode) });
             pending_seed.inner = Some(PendingSeedTask {
                 handle: task,
                 mode: ev.mode,
@@ -970,7 +969,7 @@ pub fn record_replay_on_win(
         let win_move_index = recording.moves.len().checked_sub(1);
         let replay = Replay::new(
             game.0.seed,
-            game.0.draw_mode.clone(),
+            game.0.draw_mode,
             game.0.mode,
             ev.time_seconds,
             ev.score,
@@ -2647,7 +2646,7 @@ mod tests {
         // resolves as Inconclusive — the engine treats Inconclusive
         // as winnable (see `choose_winnable_seed` doc), so the
         // helper must return 395 when started at 394.
-        let chosen = choose_winnable_seed(394, &DrawMode::DrawOne);
+        let chosen = choose_winnable_seed(394, DrawMode::DrawOne);
         assert_eq!(
             chosen, 395,
             "seed 394 is Unwinnable; the next seed (395, Inconclusive) must be accepted"

solitaire_engine/src/home_plugin.rs

@@ -430,7 +430,7 @@ fn build_home_context<'a>(
         challenge_best: stats.map_or(0, |s| s.0.challenge_best_score),
         daily_today,
         draw_mode: settings
-            .map(|s| s.0.draw_mode.clone())
+            .map(|s| s.0.draw_mode)
             .unwrap_or(DrawMode::DrawOne),
         font_res,
         difficulty_expanded,

solitaire_engine/src/pause_plugin.rs

@@ -235,7 +235,7 @@ fn toggle_pause(
         // Snapshot current level and streak at pause time.
         let level = progress.as_deref().map(|p| p.0.level);
         let streak = stats.as_deref().map(|s| s.0.win_streak_current);
-        let draw_mode = settings.as_deref().map(|s| s.0.draw_mode.clone());
+        let draw_mode = settings.as_deref().map(|s| s.0.draw_mode);
         spawn_pause_screen(
             &mut commands,
             level,

solitaire_engine/src/play_by_seed_plugin.rs

@@ -338,7 +338,7 @@ fn tick_debounce_and_spawn_solver_task(
 
     let draw_mode = settings
         .as_ref()
-        .map_or(DrawMode::DrawOne, |s| s.0.draw_mode.clone());
+        .map_or(DrawMode::DrawOne, |s| s.0.draw_mode);
     let cfg = SolverConfig::default();
     let task = AsyncComputeTaskPool::get()
         .spawn(async move { try_solve(seed, draw_mode, &cfg) });

solitaire_engine/src/replay_playback.rs

@@ -190,7 +190,7 @@ pub fn start_replay_playback(
 ) {
     use solitaire_core::game_state::GameState;
 
-    let fresh = GameState::new_with_mode(replay.seed, replay.draw_mode.clone(), replay.mode);
+    let fresh = GameState::new_with_mode(replay.seed, replay.draw_mode, replay.mode);
     commands.insert_resource(GameStateResource(fresh));
 
     // Initial `secs_to_next` uses the constant rather than reading

solitaire_engine/src/sync_plugin.rs

@@ -322,7 +322,7 @@ fn push_replay_on_win(
         }
         let replay = Replay::new(
             game.0.seed,
-            game.0.draw_mode.clone(),
+            game.0.draw_mode,
             game.0.mode,
             ev.time_seconds,
             ev.score,

solitaire_engine/src/weekly_goals_plugin.rs

@@ -82,7 +82,7 @@ fn evaluate_weekly_goals(
         let ctx = WeeklyGoalContext {
             time_seconds: ev.time_seconds,
             used_undo: game.0.undo_count > 0,
-            draw_mode: game.0.draw_mode.clone(),
+            draw_mode: game.0.draw_mode,
         };
         for def in WEEKLY_GOALS {
             if !def.matches(&ctx) {

solitaire_wasm/src/lib.rs

@@ -119,7 +119,7 @@ impl ReplayPlayer {
         let replay: Replay =
             serde_json::from_str(replay_json).map_err(|e| format!("invalid replay JSON: {e}"))?;
         let game =
-            GameState::new_with_mode(replay.seed, replay.draw_mode.clone(), replay.mode);
+            GameState::new_with_mode(replay.seed, replay.draw_mode, replay.mode);
         Ok(Self {
             game,
             moves: replay.moves,