WSL Codex sandbox hangs FastAPI/Starlette TestClient and blocks Vite localhost bind

Environment:

• Codex CLI: 0.140.0
• OS: Ubuntu 24.04 under WSL
• Terminal: Warp
• Repo path: /home/user/code/Kids-Tutor
• codex doctor sandbox: restricted filesystem + restricted network, approval

OnRequest

• Project trust_level: trusted in ~/.codex/config.toml

Problem:
Inside Codex sandbox on WSL, FastAPI/Starlette TestClient requests hang
indefinitely. The same tests pass outside the sandbox.

A second related symptom: Playwright/Vite cannot bind localhost in the sandbox
with:
Error: listen EPERM: operation not permitted 127.0.0.1:5173

Minimal repro:
```python
from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()

@app.get("/health")
def health():
return {"ok": True}

print("before")
print(TestClient(app).get("/health").status_code)
print("after")
```
Expected:
Prints 200 and exits.

Actual in Codex sandbox:
Prints "before", then hangs in Starlette/AnyIO TestClient.

Observed stack:

• starlette.testclient.py handle_request / enter
• anyio.from_thread portal wait
• asyncio selector loop waiting

Control:
Running the same repo gate outside Codex sandbox passed:

• make test -> backend 1441 passed / 216 skipped; frontend vitest 305 passed
• npx playwright test --project=chromium admin-weekly-report-review -> 6

passed when allowed to bind localhost

Impact:
Codex can produce false audit/test failures in WSL because normal local test
gates hang only inside the sandbox. This has happened more than once.