feat: add --dangerously-bypass-approvals-and-sandbox (#1384)

This PR reworks `assess_command_safety()` so that the combination of
`AskForApproval::Never` and `SandboxPolicy::DangerFullAccess` ensures
that commands are run without _any_ sandbox and the user should never be
prompted. In turn, it adds support for a new
`--dangerously-bypass-approvals-and-sandbox` flag (that cannot be used
with `--approval-policy` or `--full-auto`) that sets both of those
options.

Fixes https://github.com/openai/codex/issues/1254

codex-rs/core/src/codex.rs

@@ -1371,7 +1371,7 @@ async fn handle_container_exec_with_params(
             }
         }
         Err(CodexErr::Sandbox(error)) => {
-            handle_sanbox_error(error, sandbox_type, params, sess, sub_id, call_id).await
+            handle_sandbox_error(error, sandbox_type, params, sess, sub_id, call_id).await
         }
         Err(e) => {
             // Handle non-sandbox errors
@@ -1386,7 +1386,7 @@ async fn handle_container_exec_with_params(
     }
 }
 
-async fn handle_sanbox_error(
+async fn handle_sandbox_error(
     error: SandboxErr,
     sandbox_type: SandboxType,
     params: ExecParams,
@@ -1408,7 +1408,14 @@ async fn handle_sanbox_error(
         };
     }
 
-    // Ask the user to retry without sandbox
+    // Note that when `error` is `SandboxErr::Denied`, it could be a false
+    // positive. That is, it may have exited with a non-zero exit code, not
+    // because the sandbox denied it, but because that is its expected behavior,
+    // i.e., a grep command that did not match anything. Ideally we would
+    // include additional metadata on the command to indicate whether non-zero
+    // exit codes merit a retry.
+
+    // For now, we categorically ask the user to retry without sandbox.
     sess.notify_background_event(&sub_id, format!("Execution failed: {error}"))
         .await;