fix: make plot_array overlays respect imshow_origin

[Jammy2211]

Overview

Development tracker for the reproducible community report now preserved as PyAutoLabs Discussion #14, originally PyAutoArray#535.

plot_array passes origin=origin_imshow to the image raster, but vector overlays (mask, border, origin, grid, mesh grid, positions, lines, and quiver coordinates) remain in unchanged data coordinates. With imshow_origin: lower, this silently mirrors the raster relative to its overlays.

The defect is still present on main as of 2026-09-21.

Acceptance

• imshow_origin: upper retains current behaviour.
• imshow_origin: lower keeps overlays registered to the corresponding image features.
• Add a regression covering at least an asymmetric positions/lines overlay so a visually plausible but misregistered plot cannot silently recur.
• Preserve the distinction between display orientation and PyAutoArray's internal y-coordinate convention.
• Close this issue when the fix is merged, then mark the settling response in Discussion Get version number from env #14 as accepted.

Community context and reproducer: https://github.com/orgs/PyAutoLabs/discussions/14