feat: add remote-acpx ACP runtime backend for node dispatch

[aehrt55]

Summary

• Add pub/sub bridge (acp-node-event-bridge) using Symbol.for globalThis for cross-module-loader state sharing
• Add Mac-side ACP handler (invoke-acp) that spawns acpx subprocess per turn, streaming ndjson back as events
• Add plugin-sdk/remote-acpx surface for the remote-acpx extension
• Add claude-node extension with Claude Code CLI dispatch skill
• Wire acp.* events through node-host runner and gateway event handler
• Fix /acp spawn to resolve agents.list entries with runtime.type=acp
• Fix @marxbiotech/openclaw package name in version/update checks

Key changes

• src/gateway/acp-node-event-bridge.ts — Singleton pub/sub bridge (gateway ↔ extension)
• src/node-host/invoke-acp.ts — Mac-side acp.spawn/acp.turn/acp.kill handler
• src/gateway/server-node-events.ts — Route acp.spawned/acp.message/acp.exited/acp.error to bridge
• src/auto-reply/reply/commands-acp/shared.ts — Resolve agents.list entries for spawn

Test plan

• Deployed to magata-shiki with @marxbiotech/openclaw@2026.3.12-2
• Verified make node connects Mac to remote gateway
• Verified /acp spawn claude dispatches to Mac node via remote-acpx
• Verified acp.turn executes acpx claude on Mac and streams response back

🤖 Generated with Claude Code