Components are frames (user bug #4)

What a component holds moves with its occurrence, and picks in the world land in the
component's frame:
- Sketches and construction planes show where their component is placed (free move, joint
  drive, Capture Position); sketch.inspect reports sketch points in the world.
- frames.rs maps a command's world picks into the frame of the body they lie on (through the
  inverse of its placement: a moved component or a pasted instance), points that make new
  geometry into the active component's frame, and directions with them; instance body names
  ("Body1 (Pin:2)") become the component's body. Fillet/chamfer edges, shell/offset/draft
  faces, face extrude/revolve, sketch on face, holes, sheet metal and plastic picks, primitives,
  appearance faces, analyses. Once per command (not again for commands run by commands); the
  active-frame fallback stays for commands without a table. Nothing changes while every
  placement is the identity.
- component.move_bodies keeps a body where it is in the world (Document.body_offsets: from the
  new component's frame to the one it was made in; renames and deleted components follow).
- The UI reads the placed model (Session::world_state) for display, picking, sketch editing and
  dialogs; live previews use it once anything is placed.
Tests (engine): sketches and construction planes move (and turn) with the component; world
picks fillet, sketch, hole and make boxes in a moved component; a pick on a pasted instance;
move_bodies keeps the world place there and back; a sketch on a face follows a Move feature.
QA's s34 now runs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/ui-egui/src/tools.rs

@@ -149,7 +149,7 @@ pub fn on_click(app: &mut SolveApp, proj: &Proj, pos: Pos2) {
             });
             if let Some((id, is_point)) = hit {
                 tool.picks.push(id.clone());
-                let st = app.session.model.state();
+                let st = app.session.world_state();
                 let is_line = app
                     .session
                     .active_sketch
@@ -252,7 +252,7 @@ fn run_shape(app: &mut SolveApp, t: &Tool) -> Vec<String> {
 fn tie_snaps(app: &mut SolveApp, t: &Tool, curves: &[String]) {
     let mut ties = Vec::new();
     {
-        let st = app.session.model.state();
+        let st = app.session.world_state();
         let Some(ss) = app.session.active_sketch.and_then(|s| st.sketch(s)) else { return };
         let sk = &ss.sketch;
         let new_pts: Vec<usize> =
@@ -319,7 +319,7 @@ pub fn preview(app: &SolveApp, t: &Tool, painter: &egui::Painter, proj: &Proj) {
         return crate::sketch_tools::preview(app, t, painter, proj);
     }
     let Some(sid) = app.session.active_sketch else { return };
-    let st = app.session.model.state();
+    let st = app.session.world_state();
     let Some(ss) = st.sketch(sid) else { return };
     let to = |p: Vec2| proj.to_screen(ss.plane.to_world(p));
     let tk = crate::theme::Tokens::get();