Large-aperture (N  =  30, ﹩{r}_{{\rm{eff}}}\approx 42\mathop{.}\limits^{^{\prime\prime} }2﹩) photometry: four-night subset. Top: unweighted residual-variance period scan over 6.8–7.4 hr for k  =  1 and k  =  2 Fourier models (per-night offsets allowed). Because the formal photometric measurement errors are much smaller than the total scatter, the scan is presented as a variance-reduction/residual-variance diagnostic rather than a formal Δχ² statistic. Bottom: phase-folded light curve at P  =  7.142 hr after removing per-night offsets; the k  =  2 model refines the waveform shape while preserving internight phase coherence. The plotted error bars represent only formal measurement uncertainties and should be regarded as lower bounds to the true scatter.