Stop src/modal shadowing the modal library in the executor's Pyright check #868

Problem

The executor's Modal app modules live in src/modal/. Pyright adds src as an import root when no extraPaths is configured, so import modal in those modules resolves to the local src/modal directory instead of the installed modal library. Every modal attribute is then unknown: 47 of the executor's Pyright errors, tolerated by rules/baselines/pyright-executor.txt under sim.quality.pyright-executor (#864), come from this, and the shadowing hides real errors in the code that uses modal.

At runtime src is never an import root: the package is installed from src, and the app modules import each other as src.modal.<module> from the project directory.

Proposal

Set extraPaths = [] in the executor's [tool.pyright], a Pyright-only setting that changes nothing about how Modal loads the apps, and fix the 9 errors it exposes without growing the baseline:

• the routing-state Dict typed as possibly None in update_version_registry;
• modal.current_function_call_id() returning str | None in the budget-window batch;
• the precompute RemoteFunction protocol, which Modal functions don't satisfy;
• a segmented national span hiding a return.

Renaming or moving src/modal isn't needed.