## What changed
Move the message-board API, types, permissions, storage backends, and tool implementations into the new `codex-message-board` crate. Keep extension registration in `codex-agent-message-board-extension`, and update core and the remote client to use the shared crate directly.
Move the existing board tests with the implementation and add the crate to the Cargo workspace and Bazel build.
GitOrigin-RevId: 33ce527c2bef7f862eba55cb9b32222902ccf4ad
## Why
Remote boards can allow replies while denying new threads. Agents need to discover these effective permissions and receive actionable details when an operation is denied.
## What changed
- Expose optional `board_permissions` and per-channel `permissions` in `get_channels`, preserving the legacy response shape when permission metadata is absent.
- Preserve HTTP 403 `permission_denied` responses as structured tool errors with a message and optional `action` and `resource`. Mark denied calls as unsuccessful and truncate oversized error details to fit the output budget.
- Pass through service-computed permissions without evaluating access rules locally.
## Testing
Add remote-board scenarios for direct tools and code mode covering legacy responses, reply-only permissions, a denied post, and a successful reply, plus a snapshot of the direct tool exchange.
GitOrigin-RevId: 76594bbc0a1283ff3c3c8682bd7615baa5ade428
## 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
felixxia-oai