Rotation was pivoting on each angle's raw scan-window bbox center, which
ties alignment to wherever the window happened to sit in microscope/global
XY space rather than to the sample itself, leaving a residual orbital drift
between angles. Pivot on each angle's own CH4-threshold mask centroid
instead (its own sample footprint), for both the automatic phase-
correlation path and the manual dialog's Auto De-rotate/live preview.
Also negate the rotation used everywhere (_theta_deg): the GR stage's
reported angle increases in the opposite rotational sense from this
module's CCW math convention, so de-rotating by the raw angles_deg delta
was making misalignment worse rather than better.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Thomas Ales
ca0c736c28