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/replay_overlay/format.rs

@@ -236,9 +236,9 @@ pub(crate) fn format_suit_glyph(suit: Suit) -> &'static str {
 
 /// Pure helper — compact 2-char card label (`rank + suit glyph`) for a
 /// known card, or `"--"` for an absent top card (empty pile).
-pub(crate) fn format_card_short(card: Option<&Card>) -> String {
+pub(crate) fn format_card_short(card: Option<&(Card, bool)>) -> String {
     match card {
-        Some(c) => format!("{}{}", format_rank_short(c.rank), format_suit_glyph(c.suit)),
+        Some((c, _)) => format!("{}{}", format_rank_short(c.rank()), format_suit_glyph(c.suit())),
         None => "--".to_string(),
     }
 }