Reduce initialization work by sharing cached dependencies across containers

[banksean]

Agents spend a lot of time repeating a lot of setup work already done either on the the host or in other containers by other agent sessions.

Borrowing some ideas from CI infrastructure, sand should cache the results of these dependency fetches locally. So when you spin up a new sandbox instance, even if it has to install packages not included in the container image, it doesn't have to hit the network to get them.

• OS packages
  • apk (host dir: ~/Library/Application\ Support/Sand/caches/apk)
• Languages/runtimes
  • Go modules/builds (host dir: ~/Library/Application\ Support/Sand/caches/mise/go)
  • JS/TS
    • pnpm
    • bun
    • npm
  • Rust
  • Java
  • Python (see cache python packages cross-container #69)

[banksean]

added configurable shared go mod caching in be78574

[banksean]

mise might be a good way to handle caching for both the toolchain installations and the source dependencies.

[banksean]

The base image now includes an auto-detection script that runs mise use --global ... for go, node or python (based only on the heuristic of the presence of go.mod, package.json or requirements.txt - this could probably be made more robust)

I've removed the bespoke go-specific caching code introduced in be78574 since mise can take care of that now.

Implementation notes:

• On the host, there's a new ~/Library/Application\ Support/Sand/caches/mise dir that contains all of the cross-container caches for installers, dependencies and build artifacts.
• This feature is currently gated on a --caches-mise flag, so you have to opt-in to use it. I plan to make it enabled by default soon though.
• The first sandbox can be slow to create, but the rest are fast.
  • With a cold caches/mise dir on the host, mise has to download whatever toolchains and dependencies the project needs.
  • On subsequent sand new ... invocations (in any project on your workstation that has the same dependencies, not just the current one!), the operation should be much faster (~instant)
  • Since the mise installation steps are now part of the container creation hooks, sand and sandd stream the output from the mise script back to the CLI so users can see that it's actually doing work, and not just locked up.

[banksean]

Next up: try to cache apk packages by volume mounting /var/cache/apk to ~/Library/.../Sand/caches/apk or something like that.

[banksean]

apk package caching works now, bumping the remaining work to v0.2.0