Use external file contents for cache invalidation

[dmadisetti]

Description

cache notably fails in the cases of: randomness, network requests, and file content. With proposed external file watching (#3258), it should be possible to leverage the contents of a watched file to invalidate

@leventov

Suggested solution

Leave as is

Possibly strongly emphasize that code with side effects may produce an inconsistent cache state.

Alternative

No response

Additional context

For a broader general discussion on cache robustness see https://github.com/marimo-team/marimo/discussions/3270