fix: resolve mypy strict errors in models.py and code_utils.py #297

Job	Run time
check-linked-issue	2s
determine-changes / detect	14s
coverage	7m 21s
unit-tests (windows-latest, 3.13)	17m 5s
unit-tests (ubuntu-latest, 3.12)	7m 0s
unit-tests (ubuntu-latest, 3.10)	7m 7s
unit-tests (ubuntu-latest, 3.14)	6m 16s
e2e-python (bubble-sort-unittest, end_to_end_test_bubblesort_unittest.py, 40)	8m 6s
e2e-python (bubble-sort-pytest-nogit, end_to_end_test_bubblesort_pytest.py, 70, true)	13m 13s
unit-tests (ubuntu-latest, 3.11)	7m 16s
unit-tests (ubuntu-latest, 3.13)	7m 37s
unit-tests (ubuntu-latest, 3.9)	8m 57s
type-check	28s
e2e-python (coverage-e2e, end_to_end_test_coverage.py, black)	6m 17s
e2e-python (async-optimization, end_to_end_test_async.py, 10)	3m 6s
e2e-python (tracer-replay, end_to_end_test_tracer_replay.py, 10)	5m 54s
e2e-python (topological-sort, end_to_end_test_topological_sort_worktree.py, 5)	2m 10s
e2e-python (futurehouse-structure, end_to_end_test_futurehouse.py, 5)	2m 54s
prek / prek	37s
e2e-python (benchmark-bubble-sort, end_to_end_test_benchmark_sort.py, 5)	12m 41s
e2e-python (init-optimization, end_to_end_test_init_optimization.py, 10)	2m 28s
e2e-js	-1s
e2e-java	-1s
required checks passed	2s
	2h 6m 49s

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