Fix pasted type losing its layout bounds cache

Type pasted or imported from another app (Illustrator, PDF, SVG) arrives
without cached_bounds, which is not serialized. TextObject::bounds() then
falls back to estimate_bounds(), a rough 0.55 em per character, so the
selection box came up short of the last character and alignment looked off
until the file was saved and reopened (Session::add_document refreshes it).

Refresh the bounds of pasted text in paste_clip, covering paste and paste in
front/back/in place and every clipboard flavour, with a regression test.

crates/engine/src/cmd/edit.rs

@@ -364,6 +364,9 @@ fn paste_clip(s: &mut Session, p: &Value, mode: PasteMode, clip: &Clipboard, cho
             }
         }
         sel.set(new_ids.iter().copied());
+        // Pasted type arrives without the layout bounds cache: fill it so boxes and alignment are
+        // right away (opening the file later would, but paste must not depend on a reopen).
+        super::typecmd::refresh_bounds_of(d, &new_ids);
         Ok((new_ids, imported))
     })?;
     Ok(json!({