fix(paste): pasted associative hatches follow the pasted boundary

Paste (and WBLOCK, which shares the kernel) kept the source boundary
handles, so the pasted hatch stayed tied to the original outline or to
unrelated handles in another drawing. The COPY remap now lives at the
document level and runs for both.

Refs #1370

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/app/command_driver/clipboard.rs

@@ -543,6 +543,9 @@ pub(crate) fn paste_entities_kernel(
             handle_map.insert(source.common().handle, copied);
         }
     }
+    // A pasted associative hatch follows the pasted boundary, or drops the
+    // association when the boundary was not pasted with it. (#1370)
+    crate::scene::remap_hatch_associations(doc, &handle_map);
     let leader_links: Vec<(Handle, Handle)> = entities
         .iter()
         .filter_map(|source| {