fix: Align transformed mesh areas with their cell edges

[Jammy2211]

Summary

Compute rectangular transformed cell areas from the geometry's published transformed edges. Adapt-image weights now use the same slim-grid coordinates for both diagnostics, avoiding the oversampled-grid IndexError and matching the mapper's node-midpoint convention.

Part of #605. The baseline fails on a real 25-pixel adapt-image mapper with sub-size 2 (IndexError: index 83 ... size 25). The companion workspace regression verifies NumPy and eager/compiled JAX geometry.

API Changes

areas_transformed and areas_for_magnification now match the outer product of transformed edge spacings. Clamped guard cells can have zero area; live-cell positivity and total area are tested. edges_transformed retains its existing raw NumPy/JAX array contract. See full details below.

Test Plan

• Full PyAutoArray: 1,919 passed, 0 failed, exit 0.
• Focused geometry/interpolator: 34 passed.
• Workspace smoke: new geometry and existing rectangular likelihood, 2 passed.
• Original indexing failure reproduced; guard-cell expectations updated to explicit edge geometry after the initial suite exposed stale positivity assumptions.
• Heart YELLOW acknowledged: “manifest drift: workspace checkouts (manifest ↔ disk) — 1 mismatch(es) vs PyAutoMind/repos.yaml”. Stale: “release validation incomplete: no rehearsal for current source”. No release or merge.

Full API Changes (for automation & release notes)

Changed Behaviour

• MeshGeometryRectangular.areas_transformed: derive per-cell areas from node-midpoint edges, avoiding mismatch between oversampled coordinates and slim adapt weights.
• MeshGeometryRectangular.areas_for_magnification: inherits those corrected areas.
• Clamped guard cells may have zero area; the domain's total area remains unchanged.

Unchanged

• The standalone adaptive_rectangular_areas_from helper is untouched.
• No signature or return-wrapper changes.

Generated by the PyAutoLabs agent workflow.

[Jammy2211]

Workspace regression PR: PyAutoLabs/autolens_workspace_test#339. Merge/release the library before merging the dependent workspace regression.