refactor: consolidate card_to_id into solitaire_core

Three byte-identical copies of the stable 0..=51 card-id helper
(suit_index*13 + rank-1) lived in feedback_anim_plugin, radial_menu, and
solitaire_wasm. The WASM copy's own comment notes it MUST match the engine
for cross-platform replay parity — exactly the kind of invariant a single
source of truth should enforce.

Add `solitaire_core::card::card_to_id(&Card) -> u32` and have all three
call sites import it. No behaviour change (same formula).

cargo test --workspace and cargo clippy --workspace --all-targets -- -D warnings pass.

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

solitaire_core/src/card.rs

@@ -1 +1,23 @@
 pub use card_game::{Card, Deck, Rank, Suit};
+
+/// Maps a [`Card`] to a stable `0..=51` numeric identity, independent of the
+/// upstream `card_game::Card` bit-packing.
+///
+/// Encoding: `suit_index * 13 + (rank as u32 - 1)`, where `suit_index` is
+/// Clubs=0, Diamonds=1, Hearts=2, Spades=3 and `rank` is 1 (Ace) ..= 13 (King).
+/// The deck id is intentionally ignored so the id depends only on the visible
+/// face.
+///
+/// This is the single source of truth shared by `CardEntity` numeric tracking,
+/// deterministic per-card animation jitter, and the WASM replay layer — those
+/// must agree byte-for-byte so replay snapshots are identical across the
+/// desktop and browser builds.
+pub fn card_to_id(card: &Card) -> u32 {
+    let suit_index: u32 = match card.suit() {
+        Suit::Clubs => 0,
+        Suit::Diamonds => 1,
+        Suit::Hearts => 2,
+        Suit::Spades => 3,
+    };
+    suit_index * 13 + (card.rank() as u32 - 1)
+}