- Change background_output default from block=true to block=false
- Add documentation about system auto-notification on task completion
- Clarify that block=false returns full status info, not empty
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- 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