- cascade.py: add TYPE_CHECKING guard for TaskComplexity to fix F821
- _base.py: add noqa: F401 to re-exported agno tool imports (FileTools,
PythonTools, ShellTools, Toolkit) — these are used by other modules
- test_three_strike.py: rename unused loop var `i` to `_` (B007)
- Run tox -e format to auto-fix I001 import-sort and F401 errors
across 23 files (isort ordering and unused pytest import)
Fixes#1247