Make Any boundaries explicit for ty unsound-return-statement

[Sun Haoran (haoranpb)]

What

Fix ty unsound-return-statement: functions returning Any where a precise type is declared. Uses isinstance narrowing, bool(...), typed locals, and cast at JSON boundaries. Python only.

Part of the stack that makes ty strict (all = "error") across the whole uv workspace. Each PR fixes one rule in Python code only; the config change lands in #956.

[github-code-quality]

Code Coverage Overview

Languages: Python

Python / code-coverage/pytest

The overall line coverage in commit cab787a in the ty/strict-unsound-re... branch remains at 86%, unchanged from commit d19989f in the ty/strict-unsound-as... branch.

Show a line coverage summary of the most impacted files.

File	ty/strict-unsound-as... d19989f	ty/strict-unsound-re... cab787a	+/-
src/bcbench/eva...stgeneration.py	43%	42%	-1%
src/bcbench/col...t_codereview.py	89%	88%	-1%
src/bcbench/types.py	91%	92%	+1%
src/bcbench/com...nds/evaluate.py	76%	77%	+1%
src/bcbench/eva...te/dataquery.py	67%	69%	+2%
src/bcbench/evaluate/nl2al.py	79%	81%	+2%
src/bcbench/age...t/shared/mcp.py	92%	95%	+3%
src/bcbench/eva...st_implement.py	65%	69%	+4%
src/bcbench/evaluate/bugfix.py	47%	52%	+5%
src/bcbench/eva...quest_triage.py	55%	62%	+7%

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_{Updated October 07, 2026 13:49 UTC}