WP1 continued — the Linux/Windows session client joins Android on the shared
PresentIntervals. Apple is the remaining leg.
The metric lives on LatchClock because that is where the on-glass stamps and
the learned panel grid it quantises against already meet, so no new plumbing
and no second source of truth about the grid. Every stamp is scored,
including the sub-millisecond pairs the grid learner deliberately skips: two
presents inside one refresh is not a grid step, but it is very much a
cadence event.
The period is taken seeded-or-learned rather than learned-only, so cadence is
scored from the first window instead of waiting for the learner to converge.
Judder also becomes a trigger for the 1 Hz presenter line. That line only
fired on drops, gate holds or the debug env var — and a cadence defect
produces none of those: no drops, no holds, healthy percentiles, visibly
broken motion. Without this a desktop stream could judder for an entire
session and never emit a line, which is the same blind spot the metric exists
to close.
One honest asymmetry, recorded in the code: these stamps are CLOCK_REALTIME
(this module's domain), so a wall-clock step would forge a hitch that never
happened. It lands in the stall/disordered counters rather than the judder
ratio, which is part of why that split is worth having. Android feeds the
metric a raw monotonic stamp and has no such exposure.
Gates: cargo check + clippy --all-targets on pf-presenter clean; punktfunk-core
clippy -D warnings clean; fmt clean.
enricobuehler
53278c6f5f