CPU Spike / Crash When Switching Pre-Release <> Release

Priority: P0 Issue: #6083

ServerManager has startup guards and process cleanup, but no explicit handling for version switch conflicts.

Remaining Work

• Reproduce and profile CPU usage during release <> pre-release switch
• Check if both versions attempt to spawn kilo serve simultaneously causing port/race conflicts
• Ensure deactivate() fully terminates the server process before new version starts
• Check for file lock conflicts on shared state (e.g., agent-manager.json, CLI config)