Feature Request & Inquiry: Python Access to Named Selection Sets

## Python Access to Named Selection Sets

### Summary
In 3ds Max, **Named Selection Sets** allow users to group objects or sub-objects for quick recall and organization. While these sets are accessible via the UI, current Python is limited.
Specifically:
- It is **not possible to create a new selection set index** via Python.
- There is **no exposed API** to store custom properties or metadata within a selection set for later retrieval.

### Requested Features
1. **Create Selection Set via Python**
Ability to define a new selection set index and populate it with a list of nodes or sub-objects.

2. **Attach Custom Properties to Selection Sets**
Support for storing metadata (e.g. tags, user-defined attributes, timestamps) directly on the selection set object.

3. **Query and Modify Selection Sets Programmatically**
Full read/write access to selection set contents and properties via Python.

### Reference
For more details on Named Selection Sets, see the [3ds Max 2025 Help Documentation](https://help.autodesk.com/view/3DSMAX/2025/ENU/?guid=GUID-93B01505-5474-43D6-8B83-810BA0157A9B).

The issue names no repository files, tests, or entry points. Start by locating the 3ds Max Python integration and any existing selection-set bindings, then compare their capabilities with the linked 3ds Max 2025 documentation. Done would require an agreed API for creating, querying, modifying, and storing metadata on named selection sets.

Written by the indexing model from the issue text.