GET/POST /api/settings, /api/settings/reset, and the two-phase atomic
export/import bundle (/api/settings/export|import) move to lib/routers/settings.py
with their exclusive helpers (the relpath allowlist validator, the atomic writer,
the library-DB snapshot + sqlite integrity gate, the config-type validator, the
bundle schema). Bodies verbatim except @app->@router and the seam reads:
meta_db->appstate.meta_db, CONFIG_DIR->appstate.config_dir,
_running_version->appstate.running_version(), and _default_settings->
appstate.default_settings (the canonical defaults builder stays in server.py —
the scan + artist-links code share it — and is injected as a new seam callable).
server.py: 5,539 -> 4,478 (-1,061).
Verified: pyflakes clean (bar the pre-existing File/safe_join/tuning_name/ET);
route table IDENTICAL (143); full pytest 2397 passed (154 settings cases incl the
export→import round-trip + library-DB snapshot/restore + relpath-allowlist SSRF/
traversal guards, retargeted onto the settings module). eslint 0.
BEHAVIORAL — needs an on-device settings export→import round-trip sign-off before
merge (do not merge on green CI alone).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>