## Why
Private IP destinations always bypassed inherited upstream proxies, preventing their use for private networks reachable through an upstream VPN proxy.
## What changed
- Add `codex exec-server --proxy-private-ips-via-upstream`, also configurable with `CODEX_EXEC_SERVER_PROXY_PRIVATE_IPS_VIA_UPSTREAM=true`. The setting defaults to disabled.
- Allow permitted RFC 1918, carrier-grade NAT, and IPv6 unique-local destinations to use an applicable upstream proxy. Loopback and link-local destinations retain direct routing, and destination access policy still applies.
- Keep connections direct when no valid upstream proxy applies or `allow_upstream_proxy=false`. Errors after selecting an upstream proxy do not trigger a direct retry.
- Rename `ExecServerRuntimePaths` to `ExecServerRuntimeOptions` and carry the routing setting from executor startup into the managed network proxy.
## Testing
Add routing coverage for private address ranges, special-use addresses, and public targets with the option enabled and disabled. Verify that HTTP and CONNECT requests still enforce destination allowlists and denylists, and update the CLI help snapshot.
GitOrigin-RevId: b7c9cc7da0e0f545694a6521b74c9b36b7b92769
## What changed
Move `codex exec-server` argument definitions, transport validation, configuration loading, authentication, and shutdown orchestration from `codex-rs/cli/src/main.rs` into `codex-rs/cli/src/exec_server_command.rs`.
Expose startup through `ExecServerCommand::run`, merge the root `--strict-config` flag into the command before dispatch, and update existing argument tests to use the new entry point.
GitOrigin-RevId: 4bcc59db2bd6e1d153a366142bd0b93ad03c6951
## Why
Allow remote exec servers to connect directly to AWS-hosted registries that
authenticate registry requests and WebSocket handshakes with AWS SigV4.
## What changed
- Add `--remote-transport direct` with SigV4 profile, region, and service
options while keeping Noise as the default transport.
- Register the `direct_jsonrpc_v1` transport and carry plain exec-server
JSON-RPC messages over the authenticated WebSocket.
- Reuse direct registrations across transient disconnects, refresh them after
a `409 Conflict`, and require TLS for non-loopback endpoints.
## Testing
- Cover CLI validation and SigV4 request signing.
- Exercise direct registration, handshake retry behavior, JSON-RPC
interoperability, and process recovery after reconnecting.
GitOrigin-RevId: 0755df330ba3abe5db0a516fdaa49338d9bbe2d2
open-matt