## What changed
Expose `add_user_message` for plain-text input using the existing thread configuration, with explicit `StartIfIdle`, `Steer`, and `Queue` modes and typed admission outcomes. Expose `interrupt_turn` to interrupt a specific turn without removing queued input.
Distinguish local validation failures from unknown remote outcomes, require successful final gRPC status, and avoid automatic retries. Preserve client message identity and raw admission payloads; report duplicate admissions by original turn ID without implying current lifecycle status.
Document reconciliation requirements and extend the attach example to submit an optional message while draining events.
## Testing
Add wire-fixture tests for admission variants, request encoding, malformed responses, local validation, redacted diagnostics, uncertain RPC outcomes, final gRPC status requirements, and dropping pending submissions without retrying or interrupting.
GitOrigin-RevId: 1def92de3fc5ca8c1f89431b7ea29b9b80d64600
## What changed
Add `codex-cloud-client`, a reusable Rust client for `ThreadService.Resume` and live `ThreadService.Attach` over HTTP/2. Callers supply the native gRPC origin, bearer token, account ID, and `HttpClientFactory`.
- Reuse shared proxy, custom CA, and network policy handling for HTTPS. Reject redirects and allow plaintext HTTP only on direct loopback with unrestricted, unmanaged policy.
- Preserve notification and server-request protobuf payloads as opaque bytes and expose native gRPC status details while redacting credentials, payloads, and error details from diagnostics.
- Bound resume and attach setup to 150 seconds without retrying requests or imposing an idle deadline on live streams. Attach ends on its first error and provides no history or automatic reconnect.
- Select Rustls in `HttpClientBuilder::http2_prior_knowledge()` so HTTPS advertises `h2` through ALPN.
Include a standalone attach example and documentation of admission semantics and stream behavior.
## Testing
Add HTTP/2 fixture tests for protobuf framing, authentication metadata, status trailers, event preservation, malformed responses, stream cancellation, redirect rejection, and diagnostic redaction. Add checks for unsafe origins, network policy restrictions, and TLS `h2` advertisement.
GitOrigin-RevId: 55db70438bb5e59272c6995c67a46ced5fa28ff4