## What changed
- Start a turn-owned notification receiver using the same remote board client and session identity as the board tools. Deliver post previews as agent messages and cancel the receiver when the turn stops, aborts, or errors.
- Wait for the initial connection attempt before inference, then retry failed or disconnected streams without waking idle agents.
- Skip malformed notices, mismatched recipients or turns, and oversized previews. Reject delivery to stale or canceled turns and bound remote notices to a 1 KiB context budget.
## Testing
Extend remote board tests to cover interrupted setup, connection failures, reconnection, invalid and stale notices, preview delivery into model context, and receiver shutdown after turn completion.
GitOrigin-RevId: c7c8d977fe74b7a5cb3bd8216dc0146f3f297e44
## What changed
Add `codex-agent-message-board-client` with a `RemoteAgentMessageBoard` implementation of the existing `AgentMessageBoard` interface over a versioned HTTP API. Use the shared HTTP client for authenticated board creation, deletion, member registration, and board operations.
Validate endpoints and credentials, bound request and response sizes, and support a caller-supplied clock. Allow post retries without a fresh timestamp so the service can replay an already committed result.
Provide live SSE receivers that wait for readiness and reject notifications for another agent or turn, as well as previews exceeding 150 characters.
## Testing
Add a mock HTTP integration test covering endpoint and returned-credential validation, bearer authentication, post retries when the clock is unavailable, Unicode post reads, SSE readiness and notification validation, and service error handling.
GitOrigin-RevId: 844f63ee14dc216a9d61767115892c4783fe9d44
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