Retire legacy reference data and the external command catalog (#302)

- Remove xtask/data/fusion-catalog.tsv and xtask/data/fusion-ids.tsv.
- Remove the legacy command-id table (crates/engine/src/legacy_ids.rs) and its use in
  find_command and in the shortcut, recents and pinned-command loaders. Only SolidCraft's
  dotted ids name commands; any other id is an unknown command.
- Boundary Fill's id becomes solid.boundary_fill.
- Replace the parity report with SolidCraft's own feature checklist: `cargo xtask features`
  writes docs/features.md from the command registry.
- docs/oracle.md, docs/step-import.md (corpus section) and docs/iges-import.md: reference
  results are being rebuilt on analytic and open-source (FreeCAD) values; see #292.
  `cargo xtask oracle` and `cargo xtask step-corpus [--iges]` write these placeholders.
- AGENTS.md, CLAUDE.md, CONTRIBUTING.md, README.md, ROADMAP.md and the book describe
  SolidCraft as independent, with reference tests on analytic values and open-source tools,
  and agents do not drive or extract data from commercial CAD products.


Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -20,8 +20,8 @@ SolidCraft application feed. See [install and launch commands](https://bherbruck
 **Status: early but usable for simple parts.** 75 of 76 public reference parts
 match their analytic or FreeCAD-computed volume, area, centre of mass and bounding box
 ([docs/oracle.md](docs/oracle.md)); the other is a tracked bug.
-These checks do not establish complete geometric or workflow equivalence. Feature coverage
-is tracked in [docs/parity.md](docs/parity.md) and [ROADMAP.md](ROADMAP.md).
+These checks do not establish complete geometric or workflow equivalence. The commands SolidCraft has
+are listed by area in [docs/features.md](docs/features.md); status and plans are in [ROADMAP.md](ROADMAP.md).
 Open work and known bugs are in [GitHub issues](https://github.com/bherbruck/solidcraft/issues),
 and help is welcome: see [CONTRIBUTING.md](CONTRIBUTING.md).
 
@@ -168,6 +168,7 @@ MIT OR Apache-2.0, at your option. Developed under the
 [clean-room contribution rules](CLAUDE.md); third-party code and assets retain their
 documented licences and attribution.
 
-References to other products describe workflow comparisons and benchmark provenance.
+SolidCraft is independent. Behaviour is designed from public documentation, general CAD
+conventions and user feedback. Reference tests use analytic values and open-source tools.
 SolidCraft is not affiliated with, sponsored by or endorsed by Autodesk. Autodesk and
 Fusion are trademarks of Autodesk, Inc.