New packaging/mother/node-register-mcp accepts JSON-RPC tools/call,
inserts hw_profile into mother_hive.usb_nodes, and returns the row
with auto-derived capabilities (derive_capabilities trigger fires).
Requires one-time PostgreSQL setup on mother:
CREATE ROLE colibri WITH LOGIN;
GRANT CONNECT ON DATABASE mother_hive TO colibri;
GRANT INSERT, UPDATE ON usb_nodes TO colibri;
GRANT USAGE ON SEQUENCE usb_nodes_id_seq TO colibri;
Also updates docs to reflect 0.12 daemon behavior: hw-probe is
collected by the daemon (not the agent) and passed via CLAWDIE_HW_PROFILE
env var. COLIBRI_AUTOSPAWN_ARGS default is binary-dependent (zot->rpc,
others->--mode json).
