fix(silo): pull assembly dependencies on all open paths (#337)

SiloOrigin.openDocument() bypassed open_item() when a local file
existed, skipping dependency pulling for assemblies. Silo_Pull also
skipped dependency pulling when no revisions had files but a local
file existed.

Changes:
- SiloOrigin.openDocument(): remove local-file shortcut, route all
  opens through open_item() which already handles dependency pulling
- Silo_Pull.Activated(): add _pull_dependencies() call before opening
  existing local assembly files in the no-revisions-have-files path

Closes #337

pkg/freecad/silo_commands.py

@@ -1894,6 +1894,13 @@ class Silo_Pull:
         if not has_any_file:
             if existing_local:
                 FreeCAD.Console.PrintMessage(f"Opening existing local file: {existing_local}\n")
+                # Pull assembly dependencies before opening (#337)
+                try:
+                    item = _client.get_item(part_number)
+                except Exception:
+                    item = {}
+                if item.get("item_type") == "assembly":
+                    _pull_dependencies(part_number)
                 FreeCAD.openDocument(str(existing_local))
             else:
                 try:

pkg/freecad/silo_origin.py

@@ -315,13 +315,8 @@ class SiloOrigin:
                 FreeCAD.Console.PrintError(f"Silo open failed: {e}\n")
                 return None
 
-        # Try to find existing local file by part number
-        # (UUID lookup would require API enhancement)
-        local_path = find_file_by_part_number(identity)
-        if local_path and local_path.exists():
-            return FreeCAD.openDocument(str(local_path))
-
-        # Download from Silo
+        # Route through open_item() which pulls assembly dependencies
+        # before opening, ensuring PropertyXLink references resolve (#337)
         try:
             doc = _sync.open_item(identity)
             return doc