Move-only. The library metadata cache -- the `MetadataDB` class (4,018 lines)
plus the query helpers it owns (keyset paging cursors, the tuning grouping key,
smart-arrangement naming, tag normalisation, the startup DB-restore swap) --
moves out of server.py into a flat `lib/` module. Every moved block is
byte-identical to its server.py original; server.py is exactly origin/main
minus the six cut ranges, minus the now-dead `import contextlib`, plus the
import-back block and the constructor call site.
server.py: 14,037 -> 9,705 lines.
The one non-verbatim change is the seam that lets the class leave server.py:
`MetadataDB.__init__` now takes `config_dir` explicitly instead of reading the
module-level CONFIG_DIR, so `lib/metadata_db.py` does no IO at import
(Principle V). The `meta_db` singleton stays in server.py, so `server.meta_db`
(282 refs) and `server.app` (67 refs) resolve unchanged and no route moves.
None of the 114 `monkeypatch.setattr(server, ...)` targets moved.
Logging still goes through the `feedBack.server` logger, so log filters and
caplog assertions resolve to the same logger object.
`tests/test_settings_export_library_db.py` imports `_apply_pending_db_restore`
from metadata_db (the test moves with its subject); no other test changed.
Verified: pyflakes clean on the new module (zero undefined names, zero unused
imports) and no new undefined name in server.py; pytest 2341 passed;
node --test 1030 passed; eslint 0 errors; uvicorn boot smoke serves
/api/version, /api/library, and all three migrated plugins' src/ module graphs
(stems, studio, editor -> 200).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
