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_data/src/settings.rs

@@ -9,7 +9,7 @@ use std::io;
 use std::path::{Path, PathBuf};
 
 use serde::{Deserialize, Serialize};
-use solitaire_core::{DrawMode, game_state::DifficultyLevel};
+use solitaire_core::{DrawStockConfig, game_state::DifficultyLevel};
 
 const SETTINGS_FILE_NAME: &str = "settings.json";
 
@@ -101,7 +101,7 @@ pub struct WindowGeometry {
 pub struct Settings {
     /// Draw mode selected for new games.
     #[serde(default = "default_draw_mode")]
-    pub draw_mode: DrawMode,
+    pub draw_mode: DrawStockConfig,
     /// Linear SFX volume in `[0.0, 1.0]`. Applied to kira's SFX channel gain.
     #[serde(default = "default_sfx_volume")]
     pub sfx_volume: f32,
@@ -288,8 +288,8 @@ pub struct Settings {
     pub touch_input_mode: TouchInputMode,
 }
 
-fn default_draw_mode() -> DrawMode {
-    DrawMode::DrawOne
+fn default_draw_mode() -> DrawStockConfig {
+    DrawStockConfig::DrawOne
 }
 
 fn default_sfx_volume() -> f32 {
@@ -392,7 +392,7 @@ pub const SOLVER_DEAL_RETRY_CAP: u32 = 50;
 impl Default for Settings {
     fn default() -> Self {
         Self {
-            draw_mode: DrawMode::DrawOne,
+            draw_mode: DrawStockConfig::DrawOne,
             sfx_volume: default_sfx_volume(),
             music_volume: default_music_volume(),
             animation_speed: AnimSpeed::Normal,