refactor(core): move solver to solitaire_data, DrawMode to klondike_adapter, remove pile/solver/schema_version

- Delete solitaire_core::solver — moved wholesale to solitaire_data::solver (re-exported at crate root)
- Delete solitaire_core::pile — no external users
- Move DrawMode from game_state to klondike_adapter; re-export as solitaire_core::DrawMode
- Remove schema_version field from GameState (redundant — deserializer stamps it from the constant)
- Update all callers across solitaire_data, solitaire_engine, solitaire_assetgen, solitaire_wasm

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_core/src/game_state.rs

@@ -1,7 +1,8 @@
 use crate::card::Card;
 use crate::error::MoveError;
 use crate::klondike_adapter::{
-    KlondikeAdapter, SavedInstruction, card_from_kl, compute_time_bonus as scoring_time_bonus,
+    DrawMode, KlondikeAdapter, SavedInstruction, card_from_kl,
+    compute_time_bonus as scoring_time_bonus,
     foundation_from_slot as adapter_foundation_from_slot,
     skip_cards_from_count as adapter_skip_cards_from_count,
     tableau_from_index as adapter_tableau_from_index,
@@ -33,15 +34,6 @@ fn schema_v1() -> u32 {
     1
 }
 
-/// Whether cards are drawn one at a time or three at a time from the stock.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-pub enum DrawMode {
-    /// Draw one card from stock per turn.
-    DrawOne,
-    /// Draw three cards from stock per turn; only the top is playable.
-    DrawThree,
-}
-
 /// Difficulty tier for `GameMode::Difficulty`. Controls which pre-verified seed
 /// catalog is drawn from. `Random` skips verification entirely and uses a
 /// system-time seed — deals may or may not be winnable.
@@ -185,8 +177,6 @@ pub struct GameState {
     /// When `true`, the player may move the top card of a foundation pile back
     /// onto a compatible tableau column.
     pub take_from_foundation: bool,
-    /// Save-file schema version.
-    pub schema_version: u32,
     pub(crate) session: Session<Klondike>,
     /// Score recorded immediately before each instruction was applied.
     /// Parallel to `session.history()` during live play; used by `undo()` to
@@ -215,7 +205,6 @@ impl PartialEq for GameState {
             && self.undo_count == other.undo_count
             && self.recycle_count == other.recycle_count
             && self.take_from_foundation == other.take_from_foundation
-            && self.schema_version == other.schema_version
             && self.stock_cards() == other.stock_cards()
             && self.waste_cards() == other.waste_cards()
             && (0..4_u8)
@@ -243,7 +232,7 @@ impl Serialize for GameState {
             undo_count: self.undo_count,
             recycle_count: self.recycle_count,
             take_from_foundation: self.take_from_foundation,
-            schema_version: self.schema_version,
+            schema_version: GAME_STATE_SCHEMA_VERSION,
             saved_moves: self.saved_moves(),
         }
         .serialize(serializer)
@@ -279,9 +268,6 @@ impl<'de> Deserialize<'de> for GameState {
             // due to the pre-Phase-3 undo drift bug.
             recycle_count: 0,
             take_from_foundation: persisted.take_from_foundation,
-            // Always stamp the current schema version after a successful load so
-            // storage.rs schema checks pass and re-saving writes the v4 format.
-            schema_version: GAME_STATE_SCHEMA_VERSION,
             session: Self::new_session(persisted.seed, persisted.draw_mode),
             // score_history cannot be faithfully rebuilt from the instruction
             // history because live-play undo penalties are not recorded in
@@ -358,7 +344,6 @@ impl GameState {
             undo_count: 0,
             recycle_count: 0,
             take_from_foundation: true,
-            schema_version: GAME_STATE_SCHEMA_VERSION,
             session: Self::new_session(seed, draw_mode),
             score_history: Vec::new(),
             is_recycle_history: Vec::new(),