Health File Trend

Per-file health score over time.

Assembled from the per_file_scores map persisted on each snapshot's health_snapshots.json. With a single index the series carries one point; it fills in as more snapshots accrue.

Each point also carries unclamped_score: the score clamps at SCORE_FLOOR, so a file deep enough to sit on the floor draws a flat line no matter how much worse it gets, and the movement the chart exists to show is exactly the movement the clamp destroys. It equals score unless every point in the window recorded a depth — see file_score_series.