- Add ed25519_public_key[32] to NODEINFO struct for pubkey distribution
- Add ed25519_public_key[32] to ROUTE_BGP (derived from X25519 privkey at init)
- Add ROUTER_FLAG_SIGNED (0x08) to SVC_ROUTE_HDR flags byte
- router_send_one_flags: when is_signed, sign [hdr][payload] and append 64-byte sig
- etcp_router_recv_cb: verify Ed25519 signature when ROUTER_FLAG_SIGNED set
- New API: etcp_router_conn_send_signed()
- Drop signed packets if sender node not in routing table or no Ed25519 key
- 5 unit tests in test_etcp_router_unit.c covering OK/tampered/unknown/no-key/short
Evgeny