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_engine/src/home_plugin.rs

@@ -16,7 +16,7 @@
 use bevy::input::ButtonInput;
 use bevy::input::mouse::{MouseScrollUnit, MouseWheel};
 use bevy::prelude::*;
-use solitaire_core::{DrawMode, game_state::DifficultyLevel};
+use solitaire_core::{DrawStockConfig, game_state::DifficultyLevel};
 use solitaire_data::save_settings_to;
 
 use crate::challenge_plugin::CHALLENGE_UNLOCK_LEVEL;
@@ -432,7 +432,7 @@ fn build_home_context<'a>(
         zen_best: stats.map_or(0, |s| s.0.zen_best_score),
         challenge_best: stats.map_or(0, |s| s.0.challenge_best_score),
         daily_today,
-        draw_mode: settings.map(|s| s.0.draw_mode).unwrap_or(DrawMode::DrawOne),
+        draw_mode: settings.map(|s| s.0.draw_mode).unwrap_or(DrawStockConfig::DrawOne),
         font_res,
         difficulty_expanded,
         last_difficulty: settings.and_then(|s| s.0.last_difficulty),
@@ -620,9 +620,9 @@ fn handle_home_draw_mode_buttons(
         return;
     };
     let target = if want_one {
-        DrawMode::DrawOne
+        DrawStockConfig::DrawOne
     } else {
-        DrawMode::DrawThree
+        DrawStockConfig::DrawThree
     };
     if settings.0.draw_mode == target {
         return; // already in this mode — avoid a redundant respawn.
@@ -857,7 +857,7 @@ struct HomeContext<'a> {
     challenge_best: u32,
     daily_streak: u32,
     daily_today: Option<DailyToday>,
-    draw_mode: DrawMode,
+    draw_mode: DrawStockConfig,
     font_res: Option<&'a FontResource>,
     /// Whether the difficulty section header is currently expanded.
     difficulty_expanded: bool,
@@ -1038,7 +1038,7 @@ fn spawn_draw_mode_row(parent: &mut ChildSpawnerCommands, ctx: &HomeContext<'_>)
         ..default()
     };
 
-    let active_one = matches!(ctx.draw_mode, DrawMode::DrawOne);
+    let active_one = matches!(ctx.draw_mode, DrawStockConfig::DrawOne);
 
     parent
         .spawn(Node {