MCP push notifications (claude/channel) not received in VS Code extension

Summary

notifications/claude/channel push notifications sent from an MCP server are silently ignored by the VS Code extension, even when the server declares the experimental: { "claude/channel": {} } capability and the process is launched with --dangerously-load-development-channels via claudeProcessWrapper.

Environment

• Claude Code version: 2.1.90
• Platform: macOS (Apple Silicon, darwin arm64)
• VS Code extension (not CLI)
• MCP server: claude-peers-mcp — peer discovery and messaging between Claude Code instances

Steps to reproduce

1. Register an MCP server (scope: user) that declares experimental: { "claude/channel": {} } and sends notifications/claude/channel notifications
2. Configure claudeProcessWrapper in VS Code settings to wrap the Claude process with --dangerously-load-development-channels
3. Verify the flag is active: ps aux | grep dangerously shows claude --dangerously-load-development-channels ... ✅
4. Verify MCP tools load correctly ✅
5. Have the MCP server send a notifications/claude/channel notification to the connected client

Expected behavior

Claude receives the channel notification and reacts immediately (as documented for CLI sessions with --channels or --dangerously-load-development-channels).

Actual behavior

The notification is silently ignored. The message is consumed from the broker (marked delivered=1 in SQLite) but never surfaces in the Claude session. No error in logs.

Additional context

• The same MCP server + flag works as expected in CLI sessions launched directly with --dangerously-load-development-channels
• The VS Code extension correctly loads the MCP tools when the experimental capability is declared (without the flag, tools fail to load entirely)
• This blocks real-time inter-instance communication patterns (multiple Claude Code sessions talking to each other via a local broker) in VS Code

Workaround

Currently falling back to polling: the MCP server stores messages in a local in-memory inbox, and Claude manually calls check_messages periodically. This introduces significant latency (minimum 1 minute with CronCreate//loop) and is a poor substitute for push.

Request: Support notifications/claude/channel in the VS Code extension, consistent with CLI behavior when --dangerously-load-development-channels is active.