Generating typing for subgraphs

**Is your feature request related to a problem? Please describe.**
I want type information when using subgraph and fieldpath objects.

**Describe the solution you'd like**
Generating `.pyi` files for full type information, likely thru a CLI command in `contrib`.

**Describe alternatives you've considered**
- Using notebooks
- Large projects are easier with packages

**Additional context**
Likely would be a tall ordering and would only work on CLI or first time `.load_subgraph` is invoked.

**Implementation checklist**
- [ ] Task 1

Look at the existing CLI commands in the `contrib` module and the `load_subgraph` method to understand how subgraphs and fieldpath objects are currently handled. The goal is to generate `.pyi` type stub files, which requires understanding the GraphQL schema introspection and Python's typing system. Check if there are existing tests for type generation or subgraph loading to see the expected output format.

Scritto dal modello di indicizzazione a partire dal testo della issue.