Second commit on the B-2 replay screen-takeover redesign — the UI
that consumes the data field landed in `ab857bb`. Adds a small
green tick on the scrub bar at `replay.win_move_index / total`,
positioned so the playback cursor reaches the marker exactly when
the move it's about to apply IS the winning move.
Implementation: a new `ReplayOverlayWinMoveMarker` component
spawned alongside `ReplayOverlayScrubFill` as a sibling under the
1px scrub track. Position computed by a pure helper
`win_move_marker_pct` that returns `None` for any of: state not
`Playing`, replay's `win_move_index` is `None` (older replay
loaded from disk pre-dating the field), or empty move list. The
percentage is clamped to `[0, 100]` defensively. Marker is
absolute-positioned with `top: -1px` so the 3px-tall tick is
centered on the 1px track line — 1px above and 1px below.
Lifecycle is "spawn-time only" — the marker position never changes
during a single playback because the underlying replay is
immutable while `Playing`. Despawned with the rest of the overlay
tree when the state returns to `Inactive`.
8 new tests cover: pure helper for Inactive / Completed / no-field /
correct-position / clamp; spawn presence with field; spawn absence
without field; despawn-with-overlay lifecycle.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
funman300
52befa6199