Run on read-only filesystem (Place ./__marimo__ somewhere else)

[simon-pactum]

Description

When running on a read-only filesystem marimo will log errors as it's trying to create ./__marimo__/session

[E 251114 08:57:31 serialize:392] Failed to create parent directories: [Errno 30] Read-only file system: '/app/notebooks/example/__marimo__'
[E 251114 08:57:31 background_task:55] Error in task: [Errno 30] Read-only file system: '/app/notebooks/example/__marimo__

Similar issues have been brought up before about cache, but that's possible to re-locate somewhere else with the experimental.cache config. It would be nice if the whole __marimo__ could be moved somewhere else

Suggested solution

Config option to specify __marimo__ path