simulator: implement --load and --watch flags

[alpaylan]

The current status of the PR is halfway. The new framing of simulation runner where setup_simulation is separated from run_simulation allows for injecting custom plans easily. The PR is currently missing the functionality to update the SimulatorEnv ad hoc from the plan, as the environment tables were typically created during the planning phase.

The next steps will be to implement a function fn mk_env(InteractionPlan, SimulatorEnv) -> SimulatorEnv, add --load flag to the CLI for loading a serialized plan file, making a corresponding environment and running the simulation.

We can optionally combine this with a --save option, in which we keep a seed-vault as part of limbo simulator, corresponding each seed with its generated plan and save the time to regenerate existing seeds by just loading them into memory. I am curious to hear thoughts on this? Would the maintainers be open to adding such a seed-vault? Do you think the saved time would be worth the complexity of the approach?

[alpaylan]

Continuing with --watch.

Screen.Recording.2025-01-18.at.6.04.26.PM.mov

[alpaylan]

Watch mode is here. We can run --watch that checks the saved plan file and reruns it as it changes. Right now, it's pretty hacky in the following ways;

• There is no custom parsing for plan files. We compare the JSON representation of the Interaction Plan against the text version, detect the removed interactions and delete them from the plan. This means we cannot change the file or add anything, only add things. In the future, we can use the Limbo SQL parser for also changing values.
• It's not very well tested, as I'm not sure what kind of testing could give useful results, I just hand tested it.
• There's a lot of code duplication for the execution, as that code is not very reusable with the existing abstractions. We should look into deduplicating them.