Move-only, same shape as the MetadataDB extraction. The core-owned song/tone ->
audio-effect-provider routing index leaves server.py for a flat lib/ module.
The class body is byte-identical; server.py reconstructs exactly from
origin/main minus the cut range plus the import-back and the call site.
server.py: 9,705 -> 9,433 lines.
The only non-verbatim change is the constructor seam: `__init__` takes
`config_dir` instead of reading the module-level CONFIG_DIR, so the module does
no IO at import (Principle V). The `audio_effect_mappings` singleton stays in
server.py -- no route, no test, and none of the `monkeypatch.setattr(server, ...)`
targets move. No import went dead.
Verified: pyflakes clean on the new module; no new undefined name in server.py;
pytest 2341 passed; eslint 0 errors; boot smoke drives the extracted DB
end-to-end (POST a mapping -> GET reads it back -> audio_effects.db lands in
CONFIG_DIR, proving the config_dir seam) and all three migrated plugins still
serve their src/ module graphs.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
