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_engine/src/replay_overlay/tests.rs

@@ -2,7 +2,7 @@ use super::*;
 use chrono::NaiveDate;
 use solitaire_core::{Foundation, KlondikePile, Tableau};
 use solitaire_core::card::{Rank, Suit};
-use solitaire_core::game_state::{DrawMode, GameMode};
+use solitaire_core::{DrawMode, game_state::GameMode};
 use solitaire_core::klondike_adapter::{SavedKlondikePile, SavedTableau};
 use solitaire_data::{Replay, ReplayMove};
 
@@ -2314,7 +2314,7 @@ fn format_suit_glyph_all_suits() {
 fn format_foundations_row_empty_board() {
     let game = solitaire_core::game_state::GameState::new_with_mode(
         42,
-        solitaire_core::game_state::DrawMode::DrawOne,
+        solitaire_core::DrawMode::DrawOne,
         solitaire_core::game_state::GameMode::Classic,
     );
     assert_eq!(format_foundations_row(&game), "F: -- -- -- --");
@@ -2326,7 +2326,7 @@ fn format_foundations_row_empty_board() {
 fn format_stock_waste_row_initial_state() {
     let game = solitaire_core::game_state::GameState::new_with_mode(
         42,
-        solitaire_core::game_state::DrawMode::DrawOne,
+        solitaire_core::DrawMode::DrawOne,
         solitaire_core::game_state::GameMode::Classic,
     );
     let text = format_stock_waste_row(&game);