feat: background tasks for AgentOS (#5550)

## Summary

This adds background task execution for agents/teams in AgentOS. I.e.
pre/post hooks will be run as FastAPI background tasks instead of normal
tasks

## Type of change

- [ ] Bug fix
- [x] New feature
- [ ] Breaking change
- [ ] Improvement
- [ ] Model update
- [ ] Other:

---

## Checklist

- [ ] Code complies with style guidelines
- [ ] Ran format/validation scripts (`./scripts/format.sh` and
`./scripts/validate.sh`)
- [ ] Self-review completed
- [ ] Documentation updated (comments, docstrings)
- [ ] Examples and guides: Relevant cookbook examples have been included
or updated (if applicable)
- [ ] Tested in clean environment
- [ ] Tests added/updated (if applicable)

---

## Additional Notes

Add any important context (deployment instructions, screenshots,
security considerations, etc.)

---------

Co-authored-by: manu <[email protected]>
Co-authored-by: Harsh Sinha <[email protected]>

.cursorrules

@@ -6,6 +6,10 @@ Core Rules
 - PostgreSQL in production, SQLite for dev only
 - Start with single agent, scale up only when needed
 
+Documentation:
+- Don't use f-strings for print lines where there are no variables to format.
+- Don't use emojis in examples and print lines
+
 Basic Agent (start here):
 ```python
 from agno.agent import Agent