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/dialogs.rs

@@ -366,7 +366,7 @@ impl Dialog {
                 Kind::ReplaceFace,
                 vec![SelInput::new("Faces", PLANAR_FACES, true), SelInput::new("Target", PLANES | PLANAR_FACES, false)],
             ),
-            "SurfaceSculpt" => {
+            "solid.boundary_fill" => {
                 Dialog::new(Kind::BoundaryFill { operation: 0, cells: Vec::new(), of: Vec::new() }, vec![SelInput::new("Tools", BODIES, true)])
             }
             "solid.align" => Dialog::new(
@@ -2848,7 +2848,7 @@ fn dialog_commands(app: &SolveApp, d: &Dialog) -> Result<Vec<(String, Value)>, S
             if picked.is_empty() {
                 return Err("tick the cells to fill".into());
             }
-            ("SurfaceSculpt", json!({"tools": body_names(0), "cells": picked, "operation": OPS.get(*operation).copied().unwrap_or("new")}))
+            ("solid.boundary_fill", json!({"tools": body_names(0), "cells": picked, "operation": OPS.get(*operation).copied().unwrap_or("new")}))
         }
         Kind::Combine { operation, keep_tools } => {
             need(0, "the target body")?;
@@ -3383,7 +3383,7 @@ pub fn for_feature(app: &SolveApp, id: u64, marker: Option<usize>) -> Option<Dia
             d
         }
         FeatureKind::BoundaryFill { tools, cells, operation, remove_tools } => {
-            let mut d = start("SurfaceSculpt")?;
+            let mut d = start("solid.boundary_fill")?;
             // The cells again, ticked where a stored cell point lies in the same cell.
             let before = s.model.state_before(f.id);
             let found = fill_cells(&before, tools);