feat(data,engine): rolling replay history (last 8 wins)

Promotes replay storage from a single overwriting slot at
latest_replay.json to a rolling list of the most recent 8 wins at
replays.json so the player can revisit a memorable game even after
winning more recently.

Storage layer

solitaire_data::replay gains ReplayHistory (schema_version=1, Vec<Replay>
capped at REPLAY_HISTORY_CAP = 8) plus save_replay_history_to,
load_replay_history_from, append_replay_to_history, and
replay_history_path. append_replay_to_history inserts at the front,
drops the oldest when the cap is hit, and persists atomically via
the existing .tmp + rename pattern. The legacy single-slot helpers
are #[deprecated] but kept for one release as a migration safety
net via the new migrate_legacy_latest_replay helper.

Engine integration

game_plugin's record_replay_on_win now appends to the history
instead of overwriting latest_replay.json. On Startup, if a legacy
latest_replay.json exists but replays.json doesn't, the migration
helper seeds the new file from the legacy entry — so the player's
last v0.14.0 replay carries forward.

Stats UI

LatestReplayResource → ReplayHistoryResource holding the full
history. New SelectedReplayIndex resource (default 0 = most
recent) drives a Prev / Next / "Replay N / M" selector at the top
of the Stats overlay. ReplayPrevButton, ReplayNextButton, and
ReplaySelectorCaption marker components let the repaint system
update the caption as the selection changes. The Watch button
launches the selected replay rather than always the most recent.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

solitaire_engine/src/lib.rs

@@ -133,7 +133,8 @@ pub use selection_plugin::{
 };
 pub use splash_plugin::{SplashAge, SplashPlugin, SplashRoot};
 pub use stats_plugin::{
-    format_replay_caption, LatestReplayPath, LatestReplayResource, StatsPlugin, StatsResource,
+    format_replay_caption, LatestReplayPath, ReplayHistoryResource, ReplayNextButton,
+    ReplayPrevButton, ReplaySelectorCaption, SelectedReplayIndex, StatsPlugin, StatsResource,
     StatsScreen, StatsUpdate, WatchReplayButton,
 };
 pub use sync_plugin::{SyncPlugin, SyncProviderResource};