chore: pick up cadcodec 5b682ed (upstream acadrust sync) and cadkernel 6f046af

acadrust follows hakanaktt/acadrust main through #107, entity-record
passthrough included; cadkernel pins the same codec rev so one acadrust
stays in the graph. Upstream added BlockFlags::is_xref_unloaded, which
XATTACH now sets to false for a freshly attached reference.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/modules/insert/xattach.rs

@@ -335,6 +335,8 @@ pub fn prepare_xref_block(
         anonymous: false,
         has_attributes: false,
         is_external: false,
+        // A freshly attached reference is loaded; UNLOAD flips this later.
+        is_xref_unloaded: false,
     };
     br.xref_path = store_path.clone();
     let _ = scene.document.block_records.add(br);