refactor: persist replay/save moves as KlondikeInstruction, not pile coords (#89)

Pile-position types (Tableau, Foundation, KlondikePile, KlondikePileStack)
are runtime-only and have no serde upstream. Per Rhys's guidance, the
persistence layer now stores the moves (KlondikeInstruction) rather than
board coordinates, decoding back to runtime pile positions on demand.

Core / data:
- game_state: instruction_history() -> Vec<KlondikeInstruction>; add
  instruction_to_piles() and apply_instruction(); drop AnyInstruction.
- klondike_adapter: delete the entire Saved* serde mirror section
  (SavedTableau/Foundation/SkipCards/KlondikePile/TableauStack/
  KlondikePileStack/DstFoundation/DstTableau/SavedInstruction).
- replay: drop the bespoke ReplayMove serde mirror; Replay.moves is now
  Vec<KlondikeInstruction>; REPLAY_SCHEMA_VERSION 2 -> 3.
- storage: game_state save format v3 rejected (v4/v5 only).

Engine / wasm consumers:
- record via KlondikeInstruction (stock click = RotateStock).
- playback decodes each instruction to (from, to, count) against the
  live state via instruction_to_piles, then fires the canonical event;
  undecodable instructions are skipped with a warning, never panic.
- remove all use solitaire_data::ReplayMove and Saved* imports.

Workspace check, clippy -D warnings, and the full test suite all pass.

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

solitaire_data/src/lib.rs

@@ -163,7 +163,7 @@ pub use sync_client::{SolitaireServerClient, provider_for_backend};
 pub mod replay;
 pub use replay::{
     REPLAY_HISTORY_CAP, REPLAY_HISTORY_SCHEMA_VERSION, REPLAY_SCHEMA_VERSION, Replay,
-    ReplayHistory, ReplayMove, append_replay_to_history, load_replay_history_from,
+    ReplayHistory, append_replay_to_history, load_replay_history_from,
     migrate_legacy_latest_replay, replay_history_path, save_replay_history_to,
 };
 // `latest_replay_path` is still consumed by the engine's one-shot legacy