feat(core): take-from-foundation house rule

Add `GameState::take_from_foundation` flag (default false). When off,
Foundation→Tableau moves are blocked at the core rule layer. When on,
the top card of a foundation pile may be moved back to a compatible
tableau column (one card at a time).

Wire the matching `Settings::take_from_foundation` field through
`handle_new_game` so the player's preference applies to every new deal.
Four targeted tests cover: blocked-by-default, allowed-when-enabled,
illegal-tableau-placement, and count>1 rejection.

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

solitaire_engine/src/game_plugin.rs

@@ -490,6 +490,9 @@ fn handle_new_game(
         let chosen_seed = initial_seed;
 
         game.0 = GameState::new_with_mode(chosen_seed, draw_mode, mode);
+        if let Some(s) = settings.as_ref() {
+            game.0.take_from_foundation = s.0.take_from_foundation;
+        }
         // Reset the in-flight replay buffer — a fresh deal starts with
         // an empty move list. The previously saved replay on disk
         // (latest_replay.json) is preserved until the player wins again.