refactor: centralize filesystem permissions precedence

codex-rs/core/config.schema.json

@@ -575,10 +575,11 @@
       "type": "object"
     },
     "FileSystemAccessMode": {
+      "description": "Access mode for a filesystem entry.\n\nWhen two equally specific entries target the same path, we compare these by conflict precedence rather than by capability breadth: `none` beats `write`, and `write` beats `read`.",
       "enum": [
-        "none",
         "read",
-        "write"
+        "write",
+        "none"
       ],
       "type": "string"
     },

codex-rs/core/src/codex.rs

@@ -2851,13 +2851,15 @@ impl Session {
             AskForApproval::Never => {
                 return Some(RequestPermissionsResponse {
                     permissions: PermissionProfile::default(),
+                    scope: PermissionGrantScope::Turn,
                 });
             }
             AskForApproval::Reject(reject_config)
                 if reject_config.rejects_request_permissions() =>
             {
                 return Some(RequestPermissionsResponse {
                     permissions: PermissionProfile::default(),
+                    scope: PermissionGrantScope::Turn,
                 });
             }
             AskForApproval::OnFailure

codex-rs/core/src/codex_tests.rs

@@ -2293,6 +2293,7 @@ async fn request_permissions_emits_event_when_reject_policy_allows_requests() {
             }),
             ..Default::default()
         },
+        scope: PermissionGrantScope::Turn,
     };
 
     let handle = tokio::spawn({
@@ -2377,6 +2378,7 @@ async fn request_permissions_returns_empty_grant_when_reject_policy_blocks_reque
         Some(
             codex_protocol::request_permissions::RequestPermissionsResponse {
                 permissions: codex_protocol::models::PermissionProfile::default(),
+                scope: PermissionGrantScope::Turn,
             }
         )
     );