## Problem
When generating JSON schemas on Windows, the `codex app-server
generate-json-schema` command fails with a filename error:
```text
Error: Failed to write JSON schema for Option<()>
Caused by:
0: Failed to write .\Option<()>.json
1: The filename, directory name, or volume label syntax is incorrect. (os error 123)
```
This occurs because Windows doesn't allow certain characters in
filenames, specifically the angle brackets **<>** used in the
**Option<()>** type name.
## Root Cause
The schema generation process attempts to create individual JSON files
for each schema definition, including `Option<()>`. However, the
characters `<` and `>` are invalid in Windows filenames, causing the
file creation to fail.
## Solution
The fix extends the existing `IGNORED_DEFINITIONS` constant (which was
already being used in the **bundle generation**) to also skip
`Option<()>` when generating individual JSON schema files. This
maintains consistency with the existing behavior where `Option<()>` is
excluded from the bundled schema.
---
close#7479