macOS zero-loss disk cleanup: the caches worth knowing about

Beyond the obvious npm/pip caches, the big zero-loss reclaims on a dev Mac: Spotify PersistentCache (3GB+, quit app first, relaunch after), ~/.cache/huggingface and ~/.cache/whisper (re-downloadable models), ~/.npm/_npx, playwright/electron caches, and xcrun simctl delete unavailable for devices orphaned by deleted runtimes. After a macOS major upgrade, /Library/Developer/CoreSimulator/Caches/dyld/<old-build> is keyed to the previous host build and is permanently dead weight. Completing a pending OS update released ~34GB of APFS update snapshots that no du could see; df-used minus du-visible is how you detect that. Full arc: 233MB free to 118GB free with zero data loss.