Expose `get_godw()` helper to retrieve the central `GodWidget`
instance from anywhere in the UI code. Set the singleton in
`_async_main()` on startup.
Also,
- add docstring to `run_qtractor()` explaining trio guest mode
- type annotate `instance: GodWidget` in `run_qtractor()`
- import reorg in `._app` for cleaner grouping
- whitespace cleanup: `Type | None` -> `Type|None` throughout
- fix bitwise-or alignment: `Flag | Other` -> `Flag|Other`
(this commit-msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Gud Boi
bac8317a4a