refactor: remove card.rs / card_to_id; use card_game::Card directly (#83)

card_to_id was a frankenstein 0..=51 id shim. Replace it with card_game::Card:
- feedback_anim deal jitter now seeds off a hash of the Card itself
- radial_menu RightClickRadialState.cards: Vec<u32> -> Vec<Card>
- wasm CardSnapshot.id: u32 -> Card (serialises transparently as a plain JS
  number, the same opaque key the renderer already used; new test asserts the
  JSON id field is a number)
- wasm DebugInvariantReport deck-completeness check reworked from a [bool;52]
  index into a HashSet<Card> + Card::new reference deck; the out-of-range check
  is dropped since a Card is always valid

Delete card.rs entirely: the Card/Deck/Rank/Suit re-exports move to the crate
root and the 69 `solitaire_core::card::` import paths flatten to `solitaire_core::`.

The JS card.id is purely an opaque identity key (Map key / dataset.cardId, no
arithmetic, card faces render from rank+suit), so the value change is safe.
cargo test --workspace and clippy --workspace --all-targets -- -D warnings green.

Closes #83

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

solitaire_engine/src/touch_selection_plugin.rs

@@ -29,7 +29,7 @@
 use bevy::ecs::message::MessageReader;
 use bevy::prelude::*;
 use solitaire_core::KlondikePile;
-use solitaire_core::card::Card;
+use solitaire_core::Card;
 
 use crate::card_plugin::CardEntity;
 use crate::events::StateChangedEvent;
@@ -194,7 +194,7 @@ fn spawn_touch_highlight(
 mod tests {
     use super::*;
     use solitaire_core::Tableau;
-    use solitaire_core::card::{Card, Deck, Rank, Suit};
+    use solitaire_core::{Card, Deck, Rank, Suit};
 
     /// Three distinct test cards, used in place of the old `vec![1, 2, 3]`
     /// numeric ids. Identity is now the `Card` value.