refactor: migrate PileType → KlondikePile across core/wasm/engine

- Replace PileType with typed KlondikePile (Foundation/Tableau variants)
  throughout solitaire_core, solitaire_wasm, and solitaire_engine;
  ReplayMove now uses SavedKlondikePile for serialisation stability
- Split replay_overlay.rs into replay_overlay/ module (mod, format,
  input, update, tests) for maintainability
- Add klondike dep to solitaire_engine and solitaire_data Cargo.toml
- Add TestPileState infrastructure to game_state.rs for engine unit tests
- Rebuild solitaire_wasm pkg (js + wasm artefacts updated)

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

solitaire_engine/src/replay_playback.rs

@@ -40,6 +40,7 @@
 //! flag is threaded through, no every-callsite gate is added.
 
 use bevy::prelude::*;
+use klondike::KlondikePile;
 use solitaire_data::{Replay, ReplayMove};
 
 use crate::events::{DrawRequestEvent, MoveRequestEvent, StateChangedEvent, UndoRequestEvent};
@@ -267,9 +268,17 @@ pub fn step_replay_playback(
     }
     match &replay.moves[*cursor] {
         ReplayMove::Move { from, to, count } => {
+            let (Ok(from), Ok(to)) = (
+                KlondikePile::try_from(*from),
+                KlondikePile::try_from(*to),
+            ) else {
+                warn!("skipping replay move with invalid pile encoding at cursor {}", *cursor);
+                *cursor += 1;
+                return false;
+            };
             moves_writer.write(MoveRequestEvent {
-                from: from.clone(),
-                to: to.clone(),
+                from,
+                to,
                 count: *count,
             });
         }
@@ -370,11 +379,21 @@ fn tick_replay_playback(
             while *secs_to_next <= 0.0 && *cursor < replay.moves.len() {
                 match &replay.moves[*cursor] {
                     ReplayMove::Move { from, to, count } => {
-                        moves_writer.write(MoveRequestEvent {
-                            from: from.clone(),
-                            to: to.clone(),
-                            count: *count,
-                        });
+                        if let (Ok(from), Ok(to)) = (
+                            KlondikePile::try_from(*from),
+                            KlondikePile::try_from(*to),
+                        ) {
+                            moves_writer.write(MoveRequestEvent {
+                                from,
+                                to,
+                                count: *count,
+                            });
+                        } else {
+                            warn!(
+                                "skipping replay move with invalid pile encoding at cursor {}",
+                                *cursor
+                            );
+                        }
                     }
                     ReplayMove::StockClick => {
                         draws_writer.write(DrawRequestEvent);
@@ -536,8 +555,9 @@ mod tests {
     use crate::game_plugin::GamePlugin;
     use bevy::time::TimeUpdateStrategy;
     use chrono::NaiveDate;
+    use klondike::{KlondikePile, Tableau};
     use solitaire_core::game_state::{DrawMode, GameMode};
-    use solitaire_core::pile::PileType;
+    use solitaire_core::klondike_adapter::{SavedKlondikePile, SavedTableau};
     use std::time::Duration;
 
     /// Builds a headless `App` with `MinimalPlugins`, `GamePlugin`, and
@@ -586,8 +606,8 @@ mod tests {
             vec![
                 ReplayMove::StockClick,
                 ReplayMove::Move {
-                    from: PileType::Waste,
-                    to: PileType::Tableau(3),
+                    from: SavedKlondikePile::Stock,
+                    to: SavedKlondikePile::Tableau(SavedTableau(3)),
                     count: 1,
                 },
                 ReplayMove::StockClick,
@@ -739,8 +759,8 @@ mod tests {
             "expected 1 MoveRequestEvent (the single Move variant)",
         );
         let m = &captured_moves.0[0];
-        assert!(matches!(m.from, PileType::Waste));
-        assert!(matches!(m.to, PileType::Tableau(3)));
+        assert!(matches!(m.from, KlondikePile::Stock));
+        assert!(matches!(m.to, KlondikePile::Tableau(Tableau::Tableau4)));
         assert_eq!(m.count, 1);
     }