chore: rename unless-allow-listed to untrusted (#1378)

For the `approval_policy` config option, renames `unless-allow-listed`
to `untrusted`. In general, when it comes to exec'ing commands, I think
"trusted" is a more accurate term than "safe."

Also drops the `AskForApproval::AutoEdit` variant, as we were not really
making use of it, anyway.

Fixes https://github.com/openai/codex/issues/1250.


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* #1379
* __->__ #1378

codex-rs/core/src/config.rs

@@ -586,7 +586,7 @@ writable_roots = [
     fn create_test_fixture() -> std::io::Result<PrecedenceTestFixture> {
         let toml = r#"
 model = "o3"
-approval_policy = "unless-allow-listed"
+approval_policy = "untrusted"
 disable_response_storage = false
 
 # Can be used to determine which profile to use if not specified by