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/card_plugin.rs

@@ -17,7 +17,7 @@ use bevy::prelude::*;
 use bevy::sprite::Anchor;
 use bevy::window::WindowResized;
 use solitaire_core::{Foundation, KlondikePile, Tableau};
-use solitaire_core::card::{Card, Rank, Suit};
+use solitaire_core::{Card, Rank, Suit};
 use solitaire_core::{DrawStockConfig, game_state::GameState};
 
 use crate::animation_plugin::{CARD_ANIM_Z_LIFT, CardAnim, EffectiveSlideDuration};
@@ -2472,7 +2472,7 @@ mod tests {
     use super::*;
     use crate::game_plugin::GamePlugin;
     use crate::table_plugin::TablePlugin;
-    use solitaire_core::card::Deck;
+    use solitaire_core::Deck;
 
     /// Convenience constructor — all unit tests use Deck1.
     fn make_card(suit: Suit, rank: Rank) -> Card {