The run cycles anchor on their feet, and stride at a real cadence

Oliver: 'the motion seems very flashy and unnatural'. Two causes, both
measured: drawChar centres a frame by its total width while the racket's
reach varies across the cycle, so the BODY teleported sideways up to 28
source px on a frame swap (the female player was worst) — every frame is now
padded until its lower-third centroid sits at the frame centre (residuals
±0.2 px, the normalisation lives in _runroll.py's cut). And the hardcoded
4.5 cycles/s was tuned on 2-4 near-duplicate frames; on eight real phases it
was a strobe — rolled sets stride at TUNE.runHz (2.4), old art keeps 4.5.

In-pane: body wobble down from ~36 device px per swap to 3.2.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/config.js

@@ -41,6 +41,8 @@ export const TUNE = {
                     // the dive is what buys the pace its net clearance
   serveHardErr: 1.6,// how much a hard serve multiplies the timing scatter: pace is paid for in
                     // faults, which is what makes tap = safe second serve a real decision
+  runHz: 2.4,       // stride cycles/s for the rolled 6/8-frame run sets. The old hardcoded 4.5 was
+                    // tuned on 2-4 near-duplicate frames; on eight real phases it strobed
   serveSpin: 1.3,   // extra gravity a full-power serve carries (was a fixed 0.35). Without it the
                     // net-clearance loop ate the whole smash: a flat fast ball can't get over the
                     // tape AND come down on a target, so it got throttled back to walking pace.