fix: close the review findings on the last web wave

Full verification of the XREF/data/ARCHIVE/worker wave (three
reviewers, one forensic) found no blockers and no crossfire damage;
five majors and several minors are fixed here.

- ARCHIVE now packages XREFs: the bytes registry added by the same
  commit is consulted (the in-code 'no xref store exists' comment was
  false within the commit), and the drawing is packaged only after
  the full save preparation — without it kernel solids shipped
  without their ACIS data.
- PendingClose stores the stable tab id instead of a vector index:
  the web save now completes asynchronously, and closing a lower tab
  during the serialization window shifted indices — closing the WRONG
  tab, or panicking on a stale one. All producers and consumers
  resolve the id at use.
- The xref bytes registry is capped (6 entries, oldest evicted): every
  open, drop, and pick registered full drawing bytes with no bound —
  an OOM waiting to happen. Reopened recents register too, so any
  entry path can serve as another drawing's xref.
- A re-picked data-link source with the same name but different bytes
  no longer silently replaces the first (the browser hands back bare
  names, so two same-named files collided and every reference read
  the newer pick): the pick is refused and the user is told why.
- The unresolved-xref warning lists file names (what to drop on the
  page), not internal block names; the ZIP writer refused the ZIP64
  sentinel values (0xFFFF counts, 0xFFFFFFFF sizes/offsets) instead
  of emitting archives that send strict readers hunting for a ZIP64
  EOCD that is absent; docs note the worker-side saves.

Known follow-ups documented, not fixed here: the serde-skipped
ExtendedEntity/CadDocument raw bytes still drop on worker crossings
(needs codec accessors — upstream), and WBLOCK/SAVEALL/ARCHIVE
still serialize inline (the worker route is a small follow-up).

(cherry picked from commit 6f429f24)

Ported onto main (#1717 review): main already keys PendingClose by tab
id, so those hunks stay as on main; the ZIP64 guard is moot with the zip
crate; the unresolved-xref names split on both path separators, since
Path does not split Windows paths in the browser build.

src/app/commands/fileops.rs

@@ -585,6 +585,14 @@ impl OpenCADStudio {
             .unwrap_or_else(|| format!("{stem}.{ext}"));
         let version = self.tabs[i].scene.document.version;
 
+        // The same save preparation a web Save performs — without it the
+        // archived copy ships kernel solids without their ACIS data and a
+        // staler view/sysvar header than a real save would produce.
+        self.sync_view_state_for_save(i);
+        crate::app::update::util::sync_annotation_scale_header(&mut self.tabs[i].scene);
+        self.stamp_header_sysvars(i);
+        self.sync_solid_models_for_save(i);
+        self.tabs[i].scene.sync_native_parametric_graph();
         // The drawing itself: the same serialization a web Save performs
         // (native copies the last-saved file; the web build has none, so the
         // current document is re-serialized).