Sandbox lifecycle management with provider abstraction.
Get the glyph set for the current charset mode.
Create or connect to a sandbox of the specified provider.
This is the unified interface for sandbox creation using the provider abstraction.
Get the default working directory for a given sandbox provider.
Check that the required packages for a sandbox provider are installed.
Uses importlib.util.find_spec for a lightweight check with no actual
imports. Call this in the CLI process before spawning the server
subprocess so users get a clear, actionable error instead of an opaque
server crash.