Action matrix: every ordinary action on every face, edge, vertex and body of the design corpus (#553)

apps/solidcraft-cli/tests/action_matrix.rs tries sketch, offset/angle/mid planes, press pull, extrude from a face, hole, draft, shell, fillet, chamfer, axes, points, planes, projection, move, copy, mirror and pattern on the final bodies of 104 designs (the old design files, the examples, the 76 reference recipes, the enclosure demos, the Pi case built through the UI, eight typical parts), through the commands and picks the desktop sends, each design in its own process, with an edit round on a sample of passes. tests/action_matrix/baseline.json is a ratchet: an action that passed there and fails now fails the test; newly passing ones are reported for cargo xtask action-matrix --bless. Every CI run checks a fixed sample; the nightly Action matrix job runs the whole matrix in four parts. 30,567 of 35,576 actions pass (85.9%); results and causes in docs/action-matrix.md, one ignored reproduction per open cause (#556-#568).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/book/src/dev/testing.md

@@ -61,6 +61,14 @@ Pull requests skip a few heavy tests (each takes one to four minutes); they run
 - `solidcraft-kernel`: `tests::boolean_identity_on_tangent_primitives`
 - `solidcraft-ui-egui` scenarios: `acceptance_sensor_enclosure`
 
+The **action matrix** (`apps/solidcraft-cli/tests/action_matrix.rs`) tries every ordinary action
+(sketch, offset plane, press pull, hole, draft, shell, fillet, chamfer, construction geometry, move,
+mirror, pattern) on every face, edge, vertex and body of a corpus of designs and compares with a
+checked-in baseline: an action that passed there and fails now fails the test. Every run checks a
+fixed sample; the nightly "Action matrix" job runs it all. After a fix, record what passes now with
+`cargo xtask action-matrix --bless`. The results and the causes of the failures are in
+[the action matrix page](https://github.com/bherbruck/solidcraft/blob/main/docs/action-matrix.md).
+
 To run exactly what a pull request runs: `cargo nextest run --cargo-profile ci --profile ci`;
 add `--ignore-default-filter` for the full set. A new test that takes over a minute on CI can
 join the list (the `default-filter` in `.config/nextest.toml`) if it guards robustness rather