## Why
Account discovery and cloud configuration GETs can fail after connecting but before receiving response headers. These request failures previously bypassed system proxy fallback.
## What changed
Allow bootstrap GETs to retry through the system proxy on request errors, alongside the existing connection failure and timeout cases, when fallback is enabled.
## Testing
Add regression coverage for connections closed before response headers on `accounts/check` and `config/bundle`, verifying successful proxy retries with the original request headers. Extend coverage to ensure HTTP responses with status `401`, `403`, `407`, `429`, or `503` do not trigger fallback, and network policy denials prevent requests to both the origin and proxy.
GitOrigin-RevId: ac34c3bcfe3bd81c905a7e616d8b821879fbe2c9
## What changed
- Load `application.network` requirements at startup and explicit config/account reloads, applying local policy before authentication and cloud configuration bootstrap.
- Block traffic when policy loading fails, cancel requests that a new policy no longer permits, and reject configuration loads based on superseded policy snapshots. Local requirements edits take effect on the next explicit reload or restart.
- Bind authenticated clients to the current account and revoke them when account ownership changes. Carry policy enforcement through backend requests, realtime connections, workload identity exchanges, and code-mode gRPC streams while preserving gRPC trailers.
- Treat denied credential refreshes as policy errors without retrying them or invalidating stored credentials.
## Testing
Add regression coverage for startup restrictions, reload ordering, cancellation after restrictive or malformed requirements edits, account revocation, gRPC destination denial, workload identity cancellation, and credential preservation after denied OAuth refresh.
GitOrigin-RevId: 0cb4c720a906397e9df06675f01ecf60d741101f
## Why
Login and enterprise configuration bootstrap can fail when their endpoints are reachable only through the system proxy, before cloud configuration can enable `respect_system_proxy`.
## What changed
- Enable `features.system_proxy_fallback` by default, honor managed feature requirements, and prevent project configuration from changing it.
- Retry account discovery and cloud configuration GETs through the system proxy after connection failures or timeouts, bounding the initial request and body read to five seconds.
- Retry OAuth authorization-code exchange only on connection failures before any redirect, with a ten-second connection timeout. Reuse the successful client for the subsequent API-key exchange to avoid changing routes.
- Increase workspace discovery and cloud configuration timeouts to 15 and 20 seconds, respectively, to accommodate fallback.
## Testing
Add coverage for proxy-only browser login through the first completed turn, including cloud configuration enabling `respect_system_proxy` without a restart. Cover stalled GET bodies, preserved request headers, disabled fallback, managed requirements, and project configuration restrictions. Verify that OAuth HTTP errors, redirects followed by connection failures, and failures after sending the POST do not trigger proxy retries, while successful redirects remain supported.
GitOrigin-RevId: 854eeeac186bb4865218ce645019c1e4bff85425
## Why
Backend-backed features need to use the same outbound routing configuration as the rest of Codex.
## What changed
- Build the backend client on a route-aware client pool supplied by `HttpClientFactory`.
- Pass the configured factory through app-server account requests, cloud config loading, cloud tasks, and memory rate-limit checks.
- Preserve task query encoding, authentication headers, JSON request bodies, and ChatGPT cookie handling during the migration.
## Testing
- Add backend-client tests for proxy-policy propagation, task query encoding, bearer authentication, and JSON request bodies.
GitOrigin-RevId: c17d162e0dce9cec758df7cdeecf982207c6512b
Abhinav