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>

crates/ui-egui/src/keymap.rs

@@ -38,15 +38,10 @@ impl Keymap {
     }
     pub fn load(&mut self, v: &Value) {
         self.custom =
-            v.as_object().map(|o| o.iter().take(2000).filter_map(|(k, v)| Some((current(k), v.as_str()?.to_string()))).collect()).unwrap_or_default();
+            v.as_object().map(|o| o.iter().take(2000).filter_map(|(k, v)| Some((k.clone(), v.as_str()?.to_string()))).collect()).unwrap_or_default();
     }
 }
 
-/// Saved before the command ids were renamed: the current id.
-fn current(id: &str) -> String {
-    solvecraft_engine::legacy_ids::current_id(id).to_string()
-}
-
 /// A key press as a shortcut name: `E`, `Shift+E`, `Ctrl+Alt+K`, `F5`, `Delete`.
 pub fn key_name(key: egui::Key, mods: egui::Modifiers) -> String {
     let mut s = String::new();