- Rename omo-task to call-omo-agent with mandatory run_in_background parameter
- Implement background mode using BackgroundManager (fire-and-forget abort)
- Implement sync mode with existing subagent logic
- Fix background_cancel: use fire-and-forget abort to prevent parent session interruption
- Add call_omo_agent to tool disable list in explore/librarian agents
- Add call_omo_agent to tool disable list in BackgroundManager
🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)
- Merge background_status into background_output with block parameter
- Replace background_result references with background_output throughout codebase
- Update tool descriptions to reflect new unified API
- Remove background-tasks.json (memory-based only)
- Simplify notification messages and tool usage instructions
- Replace unreliable event-based tracking with 2-second polling
- Use SDK session.get() to detect completion (status === idle)
- Use SDK session.messages() to count tool_use parts for progress
- Auto-start polling on launch, auto-stop when no running tasks
- Resume polling on restore if running tasks exist
Fixes: Child session events not reaching plugin event handler
🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)
