fix: resolve mypy strict errors in models.py and code_utils.py #321

Job	Run time
determine-changes / detect	10s
check-linked-issue	4s
type-check	23s
coverage	7m 28s
unit-tests (ubuntu-latest, 3.13)	7m 13s
unit-tests (ubuntu-latest, 3.9)	9m 1s
unit-tests (ubuntu-latest, 3.12)	6m 54s
unit-tests (windows-latest, 3.13)	11m 26s
unit-tests (ubuntu-latest, 3.11)	6m 35s
unit-tests (ubuntu-latest, 3.10)	7m 21s
unit-tests (ubuntu-latest, 3.14)	6m 8s
prek / prek	33s
e2e-python (topological-sort, end_to_end_test_topological_sort_worktree.py, 5)	2m 42s
e2e-python (bubble-sort-pytest-nogit, end_to_end_test_bubblesort_pytest.py, 70, true)	8m 36s
e2e-python (futurehouse-structure, end_to_end_test_futurehouse.py, 5)	2m 40s
e2e-python (bubble-sort-unittest, end_to_end_test_bubblesort_unittest.py, 40)	4m 0s
e2e-python (coverage-e2e, end_to_end_test_coverage.py, black)	5m 21s
e2e-python (async-optimization, end_to_end_test_async.py, 10)	8m 33s
e2e-python (benchmark-bubble-sort, end_to_end_test_benchmark_sort.py, 5)	4m 33s
e2e-python (init-optimization, end_to_end_test_init_optimization.py, 10)	3m 10s
e2e-python (tracer-replay, end_to_end_test_tracer_replay.py, 10)	6m 53s
e2e-js	0s
e2e-java	0s
required checks passed	2s
	1h 49m 46s

Provide feedback