refactor(core): complete card_game::Card migration across engine + wasm

Finish the half-applied Card refactor. solitaire_core::card::Card is now an
alias for the opaque card_game::Card: suit()/rank() are methods, there is no
id or face_up field, and it is Clone+Eq+Hash but not Copy. Pile accessors
return Vec<(Card, bool)> where the bool is face-up.

Card identity is now the Card value itself (via Eq/Hash), not a numeric u32:
- CardEntity stores `card: Card` (was `card_id: u32`); lookups compare cards.
- Drag/selection collections and the touch/keyboard selection setters use
  Vec<Card>; CardFlippedEvent/CardFaceRevealedEvent/HintVisualEvent carry Card.
- replay_overlay and feedback/settle/deal animations updated accordingly.

solitaire_wasm: CardSnapshot derives its JSON id from suit+rank (matching the
desktop engine), and consumes the (Card, bool) pile tuples.

test-support: TestPileState tableau overrides now carry a per-card face-up flag
so tests can place face-down tableau cards. set_test_tableau_cards keeps its
Vec<Card> signature (defaulting to face-up); new set_test_tableau_cards_with_face
takes Vec<(Card, bool)>.

cargo test --workspace passes (engine lib 897 ok, 0 failed); cargo clippy
--workspace --all-targets -- -D warnings is clean. Save/serde format unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

solitaire_engine/src/events.rs

@@ -2,7 +2,7 @@
 
 use bevy::prelude::Message;
 use solitaire_core::KlondikePile;
-use solitaire_core::card::Suit;
+use solitaire_core::card::{Card, Suit};
 use solitaire_core::game_state::GameMode;
 use solitaire_data::AchievementRecord;
 use solitaire_sync::SyncResponse;
@@ -104,8 +104,8 @@ pub struct WinStreakMilestoneEvent {
 }
 
 /// Fired when a card's face-up state changes during gameplay.
-#[derive(Message, Debug, Clone, Copy)]
-pub struct CardFlippedEvent(pub u32);
+#[derive(Message, Debug, Clone)]
+pub struct CardFlippedEvent(pub Card);
 
 /// Fired by the flip animation at its midpoint — the instant the card face
 /// becomes visible (scale.x crosses zero and the phase switches to ScalingUp).
@@ -113,8 +113,8 @@ pub struct CardFlippedEvent(pub u32);
 /// Audio systems should listen to this event rather than `CardFlippedEvent`
 /// so the flip sound is synchronised with the visual reveal, not the move
 /// that triggered the animation.
-#[derive(Message, Debug, Clone, Copy)]
-pub struct CardFaceRevealedEvent(pub u32);
+#[derive(Message, Debug, Clone)]
+pub struct CardFaceRevealedEvent(pub Card);
 
 /// Achievement unlocked notification carrying the full `AchievementRecord` for
 /// the newly unlocked achievement. Consumed by the toast renderer and any
@@ -299,8 +299,8 @@ pub struct ScanThemesRequestEvent;
 /// `TablePlugin` (to tint the destination `PileMarker` gold for 2 s).
 #[derive(Message, Debug, Clone)]
 pub struct HintVisualEvent {
-    /// The `Card::id` of the source card to be highlighted.
-    pub source_card_id: u32,
+    /// The source card to be highlighted.
+    pub source_card: Card,
     /// The destination pile whose `PileMarker` should be tinted gold.
     pub dest_pile: KlondikePile,
 }