WillTools 2026-09-09 -- clean snapshot of the development repo for review

History-free snapshot of the private development repository at cbe45c5
(2026-09-09). Code, docs and public catalogue only; no plant or job
knowledge layers, no client or job names (tools/scrub.py clean). The
intro deck is left out of this snapshot because its slide images could
not be checked for job drawings.

panellift/tests/test_ignore_lateral_prestress.py

@@ -0,0 +1,15 @@
+"""`Panel.ignore_lateral_prestress` drops the in-plane prestress term from
+the corner stresses -- the plant's reference-tool convention -- and is off
+by default."""
+from panellift.model import Panel
+
+
+def test_default_is_off():
+    assert Panel(mark='X', length_ft=20.0, width_ft=10.0,
+                 thickness_in=8.0).ignore_lateral_prestress is False
+
+
+def test_flag_is_a_plain_field():
+    p = Panel(mark='X', length_ft=20.0, width_ft=10.0, thickness_in=8.0,
+              ignore_lateral_prestress=True)
+    assert p.ignore_lateral_prestress is True