First finite step toward the B-2 replay screen-takeover redesign:
the data foundation. Adds an additive optional `win_move_index:
Option<usize>` field on `Replay`, defaulting to `None` via
`#[serde(default)]` so older `latest_replay.json` /
`replays.json` files load unchanged — no `REPLAY_SCHEMA_VERSION`
bump needed since the field is purely additive and nullable.
Populated at the live recording site (`game_plugin::handle_game_won`)
via a new builder-style setter `Replay::with_win_move_index`. For
fresh recordings the value is always `Some(moves.len() - 1)`
because recording freezes on win, but storing the index
explicitly lets the playback UI read the WIN MOVE position
directly without re-deriving it on every render — and leaves
room for future recording semantics that capture post-win state.
UI consumption (the WIN MOVE marker on the scrub bar, plus the
broader screen-takeover redesign — move-log scroller, mini-
tableau preview, playback controls) lands in subsequent commits.
Test coverage: default value, builder set / set-None, on-disk
round-trip, and the legacy-JSON-loads-with-None backward-compat
contract (the test that pins the no-schema-bump claim).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
funman300
ab857bbb6e