fix(3d): move and paste ACIS solids to the right place

Solids were missing from the entity transform dispatch, so move / rotate /
scale / mirror were silently no-ops on a 3D solid (only its wires shifted)
and a pasted solid stayed at its original location. Add a Transformable impl
for Solid3D/Region/Body/Surface (delegating to acadrust, which now composes
the move into the ACIS body placement) and register them in the dispatcher.

Also make cross-drawing paste land at the cursor: the clipboard centroid is
measured in the source drawing's offset-relative frame, so correct the paste
translation by the source/target world_offset difference (zero within one
drawing). Bumps acadrust for the solid-geometry transform fixes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/mod.rs

@@ -369,6 +369,12 @@ pub(super) struct OpenCADStudio {
     clipboard: Vec<acadrust::EntityType>,
     /// Centroid of the clipboard entities (world XY plane).
     clipboard_centroid: glam::Vec3,
+    /// The source drawing's `world_offset` at copy time. The centroid above is
+    /// measured in that drawing's offset-relative frame; pasting into a drawing
+    /// with a different offset (e.g. a large-coordinate file → a fresh one)
+    /// must correct the paste translation by the offset difference, else the
+    /// objects land `source_offset − target_offset` away from the cursor.
+    clipboard_world_offset: [f64; 3],
     /// Table records (layer / linetype / text + dim style) the clipboard
     /// entities reference, captured from the source drawing at copy time so a
     /// paste into a *different* drawing can recreate any that are missing —
@@ -1721,6 +1727,7 @@ impl OpenCADStudio {
             update_notice_body: None,
             clipboard: Vec::new(),
             clipboard_centroid: glam::Vec3::ZERO,
+            clipboard_world_offset: [0.0; 3],
             clipboard_deps: ClipboardDeps::default(),
             shift_down: false,
             mtext_editor: None,