Move the Subsonic + Navidrome protocol clients and the library IPC facade
(subsonic*, navidrome*, library.ts + tests) from src/api/ into src/lib/api/,
the feature-free infra layer (plan M4, decision §10.3: shared client core → lib/).
Pure move: deep-path import specifiers @/api/* -> @/lib/api/* across ~150
consumers; no behaviour change. Domain REST (lyrics/events) and cover/analysis
infra stay in src/api/ pending their own M4 placement.
tsc 0, lint 0/0, full suite 319 files / 2353 tests green.
Theme infra (fixedThemes, theme utils), music-network presetIcon, audio-device
probe, library-index sync, and the auth*SettingsActions slices stay in the
core/global layer (consumed via @/ alias) to avoid inverting core->feature.
Psychotoxical