Class StallDetector

Absolute floor: an interval at or under this is never dead time, however large the outlier ratio

How many times the recent median an interval must exceed to count as dead time (default 4)

How many PRECEDING intervals the median is taken over (default 4 — short enough to follow a real slowdown within a few frames, long enough that one hitch cannot move the median, and EVEN so a 1:1 alternating cadence converges; see the class comment). CLAMPED to at least 2: a windowSize of 0 leaves the memory permanently empty, so every over-floor interval takes the cold-memory path and the absolute-threshold-only rule this class exists to replace is silently back, while 1 leaves a memory that follows every single hitch. outlierFactor is likewise clamped to at least 1.

A NON-FINITE knob is treated as ABSENT and falls back to the default BEFORE the clamp, because Math.max propagates NaN rather than rejecting it: Math.max(2, NaN) is NaN, and a NaN windowSize would leave recent.length > NaN permanently false — the ring never trims, so it grows without bound and pays an O(n log n) median on every frame — while a NaN outlierFactor makes every comparison false and the detector never fires at all. ±Infinity is just as bad (an infinite ring, or a factor nothing can exceed), so the guard is Number.isFinite, not an isNaN check. minGapMs needs it MOST: !(intervalMs > NaN) is true for every interval, so a NaN floor makes isStall answer false forever — dead time is never discarded at all and a single tab-resume gap folds into the FPS window of an otherwise healthy 60 fps session.