fix(silo): pull assembly dependencies on all open paths

Add _pull_dependencies() that fetches BOM children and downloads
missing files to canonical paths before an assembly document is
opened, so PropertyXLink references resolve correctly.

- Create _pull_dependencies(): iterates BOM, fetches canonical item
  description via get_item(), downloads latest file revision for each
  missing child
- Modify open_item(): detect assembly item_type and call
  _pull_dependencies() before opening
- Silo_Open: prefer open_item() when part_number is available so
  assemblies opened from search results also pull dependencies
- Silo_Pull: pull dependencies with progress dialog after main file
  download completes, before reopening the document

Closes #337

pkg/freecad/silo_commands.py

@@ -1048,6 +1048,59 @@ def get_tracked_object(doc):
     return None
 
 
+def _pull_dependencies(part_number: str) -> None:
+    """Download BOM children so PropertyXLink references resolve on open.
+
+    For each child in the BOM that is not already present locally, fetch
+    the item metadata (for canonical description) and download the latest
+    file revision to the canonical path.
+    """
+    try:
+        bom = _client.get_bom(part_number)
+    except Exception as e:
+        FreeCAD.Console.PrintWarning(f"Could not fetch BOM for {part_number}: {e}\n")
+        return
+
+    if not bom:
+        return
+
+    for entry in bom:
+        child_pn = entry.get("child_part_number", "")
+        if not child_pn:
+            continue
+
+        # Check if we already have the file locally
+        existing = find_file_by_part_number(child_pn)
+        if existing and existing.exists():
+            continue
+
+        # Get canonical item description for the filename
+        try:
+            child_item = _client.get_item(child_pn)
+            child_desc = child_item.get("description", "")
+        except Exception:
+            child_desc = entry.get("child_description", "")
+
+        dest_path = get_cad_file_path(child_pn, child_desc)
+        dest_path.parent.mkdir(parents=True, exist_ok=True)
+
+        # Find latest revision with a file
+        rev = _client.latest_file_revision(child_pn)
+        if not rev:
+            FreeCAD.Console.PrintWarning(f"No file revision for dependency {child_pn}, skipping.\n")
+            continue
+
+        rev_num = rev["revision_number"]
+        try:
+            ok = _client._download_file(child_pn, rev_num, str(dest_path))
+            if ok:
+                FreeCAD.Console.PrintMessage(f"Pulled dependency {child_pn} rev {rev_num}\n")
+            else:
+                FreeCAD.Console.PrintWarning(f"Failed to download dependency {child_pn}\n")
+        except Exception as e:
+            FreeCAD.Console.PrintWarning(f"Error downloading dependency {child_pn}: {e}\n")
+
+
 class SiloSync:
     """Handles synchronization between FreeCAD and Silo."""
 
@@ -1165,14 +1218,31 @@ class SiloSync:
         return doc
 
     def open_item(self, part_number: str):
-        """Open or create item document."""
+        """Open or create item document.
+
+        For assemblies, BOM dependencies are pulled first so that
+        PropertyXLink references resolve when the document loads.
+        """
+        # Fetch item metadata to check item_type
+        try:
+            item = self.client.get_item(part_number)
+        except Exception as e:
+            FreeCAD.Console.PrintError(f"Failed to fetch item: {e}\n")
+            item = {}
+
+        # Pull assembly dependencies before opening so links resolve
+        if item.get("item_type") == "assembly":
+            _pull_dependencies(part_number)
+
         existing_path = find_file_by_part_number(part_number)
 
         if existing_path and existing_path.exists():
             return FreeCAD.openDocument(str(existing_path))
 
+        if not item:
+            return None
+
         try:
-            item = self.client.get_item(part_number)
             return self.create_document_for_item(item, save=True)
         except Exception as e:
             FreeCAD.Console.PrintError(f"Failed to open: {e}\n")
@@ -1365,10 +1435,10 @@ class Silo_Open:
         # inside the dialog's nested event loop, which can cause crashes.
         data = _open_after_close[0]
         if data is not None:
-            if data.get("path"):
-                FreeCAD.openDocument(data["path"])
-            else:
+            if data.get("part_number"):
                 _sync.open_item(data["part_number"])
+            elif data.get("path"):
+                FreeCAD.openDocument(data["path"])
 
     def IsActive(self):
         return True
@@ -1908,6 +1978,18 @@ class Silo_Pull:
 
         FreeCAD.Console.PrintMessage(f"Pulled revision {rev_num} of {part_number}\n")
 
+        # Pull assembly dependencies before reopening
+        if item.get("item_type") == "assembly":
+            dep_progress = QtGui.QProgressDialog(
+                f"Pulling dependencies for {part_number}...", None, 0, 0
+            )
+            dep_progress.setWindowModality(2)  # Qt.WindowModal
+            dep_progress.setMinimumDuration(0)
+            dep_progress.setValue(0)
+            QtGui.QApplication.processEvents()
+            _pull_dependencies(part_number)
+            dep_progress.close()
+
         # Close existing document if open, then reopen
         if doc and doc.FileName == str(dest_path):
             FreeCAD.closeDocument(doc.Name)