installConfig
Installs initial configuration data (local info and remote nodes) into the database.
Used during the initial connection handshake. When the connected device's identity changed since the last session (firmware 2.8 derives the node number from the public key, and an erase-and-reflash mints new keys), the stale identity is migrated or removed as part of the install.
Return
node numbers whose rows were removed by that identity migration, so callers can evict them from in-memory caches.