refactor: replace local DrawMode with upstream klondike::DrawStockConfig (#82)

DrawMode was a 1:1 mirror of klondike::DrawStockConfig (DrawOne/DrawThree).
Delete it and use the upstream type everywhere; re-export DrawStockConfig from
solitaire_core. config_for assigns draw_stock directly and draw_mode() returns
session.config().inner.draw_stock.

Serde is unchanged — DrawStockConfig serialises to the same "DrawOne"/"DrawThree"
named variants, so persisted game_state.json / replay JSON stay byte-compatible
(no migration). Field/method/variable names containing draw_mode are unchanged.

35 files, mechanical type swap across all crates. Implemented via a multi-agent
workflow (core → per-crate consumers → verify). cargo test --workspace and
clippy --workspace --all-targets -- -D warnings green.

Closes #82

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

solitaire_core/src/proptest_tests.rs

@@ -1,9 +1,8 @@
 use card_game::{Card, Game};
-use klondike::{Foundation, KlondikePile, KlondikeInstruction, SkipCards, Tableau};
+use klondike::{DrawStockConfig, Foundation, KlondikePile, KlondikeInstruction, SkipCards, Tableau};
 use proptest::prelude::*;
 
 use crate::game_state::GameState;
-use crate::klondike_adapter::DrawMode;
 use crate::klondike_adapter::{
     InvalidSavedInstruction, SavedDstFoundation, SavedDstTableau, SavedFoundation,
     SavedInstruction, SavedKlondikePile, SavedKlondikePileStack, SavedSkipCards, SavedTableau,
@@ -52,8 +51,8 @@ fn all_cards(game: &GameState) -> Vec<Card> {
     cards
 }
 
-fn draw_mode_strategy() -> impl Strategy<Value = DrawMode> {
-    prop_oneof![Just(DrawMode::DrawOne), Just(DrawMode::DrawThree)]
+fn draw_mode_strategy() -> impl Strategy<Value = DrawStockConfig> {
+    prop_oneof![Just(DrawStockConfig::DrawOne), Just(DrawStockConfig::DrawThree)]
 }
 
 /// Apply a sequence of random actions to a game, silently ignoring errors.