fix(acp): disable MessageBus in ACP mode to avoid 30s timeout

[codefromthecrypt]

Summary

Disables enableMessageBusIntegration when --experimental-acp is set, fixing a 30s delay before tool confirmation in ACP mode.

Details

Problem

In ACP mode, every tool requiring confirmation waits 30 seconds before proceeding.

Cause

getMessageBusDecision() publishes TOOL_CONFIRMATION_REQUEST and waits for CoreToolScheduler to respond. In ACP mode, zedIntegration.ts handles tool confirmation via requestPermission() JSON-RPC instead - there's no subscriber. The 30s timeout fires before falling back to ASK_USER.

Fix

Before (ACP mode):
+----------+  TOOL_CONFIRMATION_REQUEST  +--------------+
|  Tool    | --------------------------> |  MessageBus  |
|          |                             |  (no sub)    |
|          | <------ 30s timeout ------- |              |
|          |                             +--------------+
|          | then getConfirmationDetails()
|          | then requestPermission() to ACP client
+----------+

After (ACP mode, MessageBus disabled):
+----------+
|  Tool    | getConfirmationDetails() immediately
|          | then requestPermission() to ACP client
+----------+

Set enableMessageBusIntegration=false when argv.experimentalAcp is true.

Pre-Merge Checklist

• [ ] Updated docs/README (if needed) - N/A
• [x] Added/updated tests - Added unit test in config.test.ts
• [ ] Noted breaking changes (if any) - None

[gemini-code-assist[bot]]

Summary of Changes

Hello @codefromthecrypt, I'm Gemini Code Assist[^1]! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a significant performance bottleneck in the experimental ACP mode, where users experienced a 30-second timeout for every tool confirmation. The root cause was identified as the MessageBus attempting to publish requests without an active subscriber in ACP mode, leading to an unnecessary delay. The solution involves a targeted configuration change to disable the MessageBus integration specifically when ACP mode is enabled, thereby streamlining the tool confirmation process and improving responsiveness.

Highlights

• Performance Fix for ACP Mode: Resolved a 30-second delay in tool confirmation within ACP (Agent Control Plane) mode by disabling the MessageBus integration when the --experimental-acp flag is active.
• Conditional MessageBus Disablement: The enableMessageBusIntegration setting is now conditionally set to false if argv.experimentalAcp is true, preventing the MessageBus from waiting for a non-existent subscriber in ACP mode.
• New Unit Test: A new unit test has been added to config.test.ts to ensure that enableMessageBusIntegration is correctly disabled when --experimental-acp is provided as a command-line argument.

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