mount fallback

[luke-lombardi]

Summary by cubic

Add a durable stub-code cache that prefers a disk mount when enabled and falls back to a temp dir when not. Also adds CAP_SYS_RESOURCE to Docker-in-Docker capabilities to support nested runc.

• New Features

  • Stub-code cache uses disk cache when enabled and a mount path is set; otherwise it uses a temp path. Cache is reused across managers.
  • Worker now passes pool config to the mount manager, so pool-level cache enable/disable and mount path overrides are respected.

• Bug Fixes

  • Include CAP_SYS_RESOURCE in Docker-in-Docker capabilities to satisfy nested runc requirements.

^{Written for commit 3436cf1. Summary will update on new commits.}