Retry the agent host IPC connect on a slow-boot channel-registration timeout

[vijayupadya]

Summary

The local agent host is reached from each window over a MessagePort IPC channel named agentHostProtocol. On a slow host boot the process registers that channel only after the IPC ChannelServer's 1s unknown-channel timeout, so the renderer's connect() call is rejected with a transient "Channel name 'agentHostProtocol' timed out after 1000ms". The local transport has no reconnect, so it treats this as fatal and closes permanently — the connection's rootState never hydrates, no agents are advertised, and the agent host option goes missing from the session-target picker.

This change retries that one transient condition instead of giving up.

Fix

AgentHostIpcChannelTransport.connect() now retries the upstream connect while the agent host is still registering its channel:

• Retries only the transient 'Unknown channel' timeout; any other error is surfaced unchanged.
• Bounded backoff (250ms → 2s cap, ~20s total budget); on exhaustion it throws exactly as before, so a genuinely-broken host still surfaces an error.
• The backoff is cancelled on dispose() (via a CancellationTokenSource), matching the file's convention that every delay timer is cancelled on teardown.
• Frame/close listeners are subscribed once — the IPC ChannelServer buffers event-listens to a not-yet-registered channel and flushes them on registration, so no double-subscription across retries.

Tests

agentHostIpcChannelTransport.test.ts:

• retries a transient 'Unknown channel' timeout until the host registers its channel (and subscribes listeners exactly once),
• does not retry a non-transient connect error,
• gives up once the retry budget is exhausted,
• stops retrying once the transport is disposed.

[Copilot]

Pull request overview

Adds bounded retry handling for transient agent-host IPC channel registration timeouts.

Changes:

• Adds cancellable exponential-backoff connection retries.
• Adds tests for success, failure, exhaustion, disposal, and listener counts.

Show a summary per file

File	Description
agentHostIpcChannelTransport.ts	Implements retry and cancellation logic.
agentHostIpcChannelTransport.test.ts	Tests retry behavior and teardown.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced