## Description
Introduced `ExternalSandbox` policy to cover use case when sandbox
defined by outside environment, effectively it translates to
`SandboxMode#DangerFullAccess` for file system (since sandbox configured
on container level) and configurable `network_access` (either Restricted
or Enabled by outside environment).
as example you can configure `ExternalSandbox` policy as part of
`sendUserTurn` v1 app_server API:
```
{
"conversationId": <id>,
"cwd": <cwd>,
"approvalPolicy": "never",
"sandboxPolicy": {
"type": ""external-sandbox",
"network_access": "enabled"/"restricted"
},
"model": <model>,
"effort": <effort>,
....
}
```
Replaces the `include_default_writable_roots` option on
`sandbox_workspace_write` (that defaulted to `true`, which was slightly
weird/annoying) with `exclude_tmpdir_env_var`, which defaults to
`false`.
Though perhaps more importantly `/tmp` is now enabled by default as part
of `sandbox_mode = "workspace-write"`, though `exclude_slash_tmp =
false` can be used to disable this.
Without this change, it is challenging to create integration tests to
verify that the folders not included in `writable_roots` in
`SandboxPolicy::WorkspaceWrite` are read-only because, by default,
`get_writable_roots_with_cwd()` includes `TMPDIR`, which is where most
integrationt
tests do their work.
This introduces a `use_exact_writable_roots` option to disable the
default
includes returned by `get_writable_roots_with_cwd()`.
---
[//]: # (BEGIN SAPLING FOOTER)
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* #1765
* __->__ #1785
Anton PanasenkoandGitHub
Michael BolinandGitHub