The onContactRemoved/onChannelRemoved hooks already clear every NodePrefs
field keyed on a contact pubkey or channel index (verified complete), but the
convention was opt-in with no reminder — new per-entity state could silently
forget to register, the class of bug fixed earlier this session.
Add a CONTRACT comment above each hook listing what it covers and instructing
additions to land there, plus a terse [del->onContactRemoved] /
[del->onChannelRemoved] tag on each of the eight keyed fields in NodePrefs.h.
Now editing either side (struct field or hook) points at the other. Comments
only; no behaviour change.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>