Autofixes the genuine lint behind the CodeQL py/unused-import and
py/unused-local-variable note-level alerts — actually removing the dead
code rather than dismissing it. 68 safe fixes via 'ruff check --select
F401,F841 --fix' across 29 backend files (dead stdlib/symbol imports like
io/sys/json/torch/typing.Optional and unused locals). Only ruff's safe
fixes applied — the 9 'unsafe' fixes and the audio_dsp numpy availability
import were left untouched.
Not touched: empty-except (needs per-site judgement, not autofixable);
frontend js/unused-local-variable (eslint no-unused-vars has no autofix);
the loopback-low-risk path/log/stack-trace alerts (real, left visible).
Verified: full tests/ suite unchanged at 601 passed (the 2 test_supertonic3
failures are pre-existing on main, local .venv state, green in CI).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
