Phase 4 of CAD_ASSESSMENT_AND_PLAN.md: remove the second copy of things
the module carried alongside their replacements. No behaviour change.
Removed, after confirming each has no live caller:
- The entire LegacyCommand system: the trait, LegacyCommandCtx,
LegacyUndoRedoStack and the six LegacyMovePart/Resize/Rotate/Add/Delete/
ModifyPart structs, plus their tests. The editor has used the Command /
UndoRedoStack pair since v19; the legacy set was still exported and
still maintained, so grepping for a command type returned two answers.
- CadViewport::legacy_ctx(), which nothing called.
- CommandError::Legacy, which was never constructed.
- The duplicate DofConstraint in mod.rs and its two bridge From impls.
Production reads cad_scene::DofConstraint exclusively; the legacy struct
existed only so a conversion test could round-trip it.
- Three dead functions in exporters.rs. The dead write_3d_viewer also
carried a bug the live path does not: it wrote an absolute filesystem
path into the exported viewer's <model-viewer src>, which breaks the
moment the folder is copied anywhere.
Renamed LegacyCommandCtxHolder -> CommandBorrows. Despite the name it
holds the *new* UndoRedoStack and is the split-borrow helper for the live
command path.
Also refreshed the v10/v13/v18b archaeology comments that referenced the
deleted types, and ported bench_command_execute_overhead to the live
Command/CadCommandCtx path so the measurement survives.
1,588 lines removed: commands.rs 1863 -> 1318, tests.rs 3754 -> 2840,
exporters.rs 186 -> 93.
Tests: 728 -> 714 passing, 0 failing. The 29 removed all exercised the
deleted system; verified by diffing the full test-name list before and
after, which also caught 16 live-system tests that merely *mentioned* a
Legacy type in passing and had to be kept.
Rebasing onto origin/main also required repairing that branch, which did
not compile (4 errors) and so had never run its own tests:
- lookup.rs: an over-eager .clone() removal left *bt.category, deref'ing a
String field to an unsized str and breaking the key type.
- estimate_store.rs: two different tests shared one name; renamed both to
say what they assert.
- Once building, 3 tests failed. EstimateStore::dispatch took an undo
snapshot and emitted UndoRedoChanged even when the command was a no-op,
so a rejected out-of-range edit still consumed an undo slot and cleared
the redo stack. Command::Initialize also never cleared the room list, so
re-initialising kept the previous run's rooms.
- spreadsheet-ui/workspace.rs: missing `use crate::model::WorkspaceModel`.
