add a slash command to grant sandbox read access to inaccessible directories (#11512)

There is an edge case where a directory is not readable by the sandbox.
In practice, we've seen very little of it, but it can happen so this
slash command unlocks users when it does.

Future idea is to make this a tool that the agent knows about so it can
be more integrated.

codex-rs/core/src/lib.rs

@@ -79,6 +79,7 @@ pub mod review_format;
 pub mod review_prompts;
 mod thread_manager;
 pub mod web_search;
+pub mod windows_sandbox_read_grants;
 pub use codex_protocol::protocol::InitialHistory;
 pub use thread_manager::NewThread;
 pub use thread_manager::ThreadManager;